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  • Intersection of two querysets in django

    - by unagimiyagi
    Hello, I can't do an AND on two querysets. As in, q1 & q2. I get the empty set and I do not know why. I have tested this with the simplest cases. I am using django 1.1.1 I have basically objects like this: item1 name="Joe" color = "blue" item2 name="Jim" color = "blue" color = "white" item3 name="John" color = "red" color = "white" Is there something weird about having a many-to-many relationship or what am I missing? queryset1 = Item.objects.filter(color="blue") this gives (item1, item2) queryset2 = Item.objects.filter(color="white") this gives (item2, item3) queryset1 & queryset2 gives me the empty set [] The OR operator works fine (I'm using "|" ) Why is this so?

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  • Jlabel with alpha value

    - by jouzef19
    Hi: i have jLabel and i want to change its opacity (alpha value) each one second , i tried something like that but its not change each one second , jlable change its opacity with last alpha value . Color color = jLabel1.getBackground(); int alpha = 255; long initTime = System.currentTimeMillis(); while(true){ if(System.currentTimeMillis() - initTime >= 1000){ initTime = System.currentTimeMillis(); alpha -=1; Color color2 = new Color(color.getRed(),color.getGreen(),color.getBlue(),alpha); jLabel1.setBackground(color2); } if(alpha<=0) break; }

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  • Pointers to Derived Class Objects Losing vfptr

    - by duckworthd
    To begin, I am trying to write a run-of-the-mill, simple Ray Tracer. In my Ray Tracer, I have multiple types of geometries in the world, all derived from a base class called "SceneObject". I've included the header for it here. /** Interface for all objects that will appear in a scene */ class SceneObject { public: mat4 M, M_inv; Color c; SceneObject(); ~SceneObject(); /** The transformation matrix to be applied to all points of this object. Identity leaves the object in world frame. */ void setMatrix(mat4 M); void setMatrix(MatrixStack mStack); void getMatrix(mat4& M); /** The color of the object */ void setColor(Color c); void getColor(Color& c); /** Alter one portion of the color, leaving the rest as they were. */ void setDiffuse(vec3 rgb); void setSpecular(vec3 rgb); void setEmission(vec3 rgb); void setAmbient(vec3 rgb); void setShininess(double s); /** Fills 'inter' with information regarding an intersection between this object and 'ray'. Ray should be in world frame. */ virtual void intersect(Intersection& inter, Ray ray) = 0; /** Returns a copy of this SceneObject */ virtual SceneObject* clone() = 0; /** Print information regarding this SceneObject for debugging */ virtual void print() = 0; }; As you can see, I've included a couple virtual functions to be implemented elsewhere. In this case, I have only two derived class -- Sphere and Triangle, both of which implement the missing member functions. Finally, I have a Parser class, which is full of static methods that do the actual "Ray Tracing" part. Here's a couple snippets for relevant portions void Parser::trace(Camera cam, Scene scene, string outputFile, int maxDepth) { int width = cam.getNumXPixels(); int height = cam.getNumYPixels(); vector<vector<vec3>> colors; colors.clear(); for (int i = 0; i< width; i++) { vector<vec3> ys; for (int j = 0; j<height; j++) { Intersection intrsct; Ray ray; cam.getRay(ray, i, j); vec3 color; printf("Obtaining color for Ray[%d,%d]\n", i,j); getColor(color, scene, ray, maxDepth); ys.push_back(color); } colors.push_back(ys); } printImage(colors, width, height, outputFile); } void Parser::getColor(vec3& color, Scene scene, Ray ray, int numBounces) { Intersection inter; scene.intersect(inter,ray); if(inter.isIntersecting()){ Color c; inter.getColor(c); c.getAmbient(color); } else { color = vec3(0,0,0); } } Right now, I've forgone the true Ray Tracing part and instead simply return the color of the first object hit, if any. As you have no doubt noticed, the only way the computer knows that a ray has intersected an object is through Scene.intersect(), which I also include. void Scene::intersect(Intersection& i, Ray r) { Intersection result; result.setDistance(numeric_limits<double>::infinity()); result.setIsIntersecting(false); double oldDist; result.getDistance(oldDist); /* Cycle through all objects, making result the closest one */ for(int ind=0; ind<objects.size(); ind++){ SceneObject* thisObj = objects[ind]; Intersection betterIntersect; thisObj->intersect(betterIntersect, r); double newDist; betterIntersect.getDistance(newDist); if (newDist < oldDist){ result = betterIntersect; oldDist = newDist; } } i = result; } Alright, now for the problem. I begin by creating a scene and filling it with objects outside of the Parser::trace() method. Now for some odd reason, I cast Ray for i=j=0 and everything works wonderfully. However, by the time the second ray is cast all of the objects stored in my Scene no longer recognize their vfptr's! I stepped through the code with a debugger and found that the information to all the vfptr's are lost somewhere between the end of getColor() and the continuation of the loop. However, if I change the arguments of getColor() to use a Scene& instead of a Scene, then no loss occurs. What crazy voodoo is this?

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  • How do I set the rounded corner radius of a color drawable using xml?

    - by Jay Askren
    On the android website, there is a section about color drawables. Defining these drawables in xml looks like this: <resources> <drawable name="solid_red">#f00</drawable> <drawable name="solid_blue">#0000ff</drawable> <drawable name="solid_green">#f0f0</drawable> </resources> In the java api, they have thr following method to define rounded corners: setCornerRadius(float radius) Is there a way to set the rounded corners in the xml?

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  • How to change the text color in a disabled edit box using MFC?

    - by anand.arumug
    Hello all, I have a dialog in which the edit box is disabled but the text should be displayed in red instead of the default grey. I tried the following: void CMyEdit::OnEnable(BOOL bEnable) { CEdit::OnEnable(bEnable); if (bEnable) { m_BackGroundColor = kRGBWhite; } else { m_BackGroundColor = kRGBDefaultGray; } m_TextColor = kRGBRed; m_BackgroundBrush.DeleteObject(); m_BackgroundBrush.CreateSolidBrush(m_BackGroundColor); Invalidate(); } But its still displaying the text in grey only. But if I remove the base class call CEdit::OnEnable(bEnable); then new text color takes effect. Can anyone explain whats wrong in the code? Thanks for your time. cheers...

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  • jQuery UI: How to change the color of a ProgressBar?

    - by IronGoofy
    I've set up a simple jQueryUI progressbar: <script type="text/javascript"> $(function() { $("#progressbar").progressbar({ value: 35 }); }); </script> <div id="progressbar"> </div> Now, I'd like to color the of the bar based on it's value (e.g. <10 red, <50 yellow, 50 green). How do I do this? Note: There are similar questions, but the answers were not clear enough to help me get things done. Hopefully, someone can point out an easier way or provide more detailed instructions. Thanks.

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  • When marking an item (changing background color) in ListView it's repeating for other items.

    - by Adi
    If I want to mark the second item I'm doing the following code: This code is from my Adapter that extends ArrayAdapter : if (convertView == null) { LayoutInflater mInflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); convertView = mInflater.inflate(R.layout.channel_list, null); } MyContent o = items.get(position); if (o != null) { TextView tt = (TextView) convertView.findViewById(R.id.toptext); TextView bt = (TextView) convertView.findViewById(R.id.bottomtext); if (tt != null) { tt.setText(o.Top()); } if(bt != null){ bt.setText(o.Bottom()); } if(position == 2) { convertView.setBackgroundColor(R.color.selectem_color); } } return convertView; It will show the list view but mark every 9'th item after this item (the 11'th item 13'th and so on). Does anyone know what's the reason?

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  • How to set Single GtkLebel Color to while using gtkrc?

    - by PP
    How to set Single GtkLebel Color to while using gtkrc? I tried to set as follows: In rc file: style "tc-theme-label-white" { xthickness = 1 ythickness = 1 font_name = "Sans Bold 8" text[NORMAL] = "#FFFFFF" text[INSENSITIVE] = "#434346" text[PRELIGHT] = "#FFFFFF" text[SELECTED] = "#FFFFFF" text[ACTIVE] = "#FFFFFF" } widget "*.my-theme-label" style:highest "my-theme-label" //And in code i have written. Gtk *label = gtk_new_label(null); gtk_widget_set_name(label_ptr, "my-theme-label"); Is this the write way of doing it? as usual it is not working. :p Thanks, PP.

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  • how can i set the background color of a particular button in iphone ?

    - by suchita
    for this I used btnName1 = [ColorfulButton buttonWithType:UIButtonTypeRoundedRect]; btnName1.frame=CGRectMake(45,146,220,40); [btnName1 setTitle:@"Continue" forState:UIControlStateNormal]; [btnName1 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal]; [btnName1 setImage:[UIImage imageNamed:@"green.png"] forState:UIControlStateNormal]; UIImage *img =[UIImage imageWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"greenish" ofType:@"png"]]; UIImage *strechableImage = [img stretchableImageWithLeftCapWidth:12 topCapHeight:0]; [btnName1 setBackgroundImage:strechableImage forState:UIControlStateNormal]; [btnName1 setNeedsDisplay]; [InfoView addSubview:btnName1]; it's correctly working on iphone simulator but not on ipod(color not show in ipod)

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  • Checking for multiple images loaded

    - by Stanni
    Hi, I'm using the canvas feature of html5. I've got some images to draw on the canvas and I need to check that they have all loaded before I can use them. I have declared them inside an array, I need a way of checking if they have all loaded at the same time but I am not sure how to do this. Here is my code: var color = new Array(); color[0] = new Image(); color[0].src = "green.png"; color[1] = new Image(); color[1].src = "blue.png"; Currently to check if the images have loaded, I would have to do it one by one like so: color[0].onload = function(){ //code here } color[1].onload = function(){ //code here } If I had a lot more images, Which I will later in in development, This would be a really inefficient way of checking them all. How would I check them all at the same time?

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  • [JavaScript] Checking for multiple images loaded.

    - by Stanni
    Hi, I'm using the canvas feature of html5. I've got some images to draw on the canvas and I need to check that they have all loaded before I can use them. I have declared them inside an array, I need a way of checking if they have all loaded at the same time but I am not sure how to do this. Here is my code: var color = new Array(); color[0] = new Image(); color[0].src = "green.png"; color[1] = new Image(); color[1].src = "blue.png"; Currently to check if the images have loaded, I would have to do it one by one like so: color[0].onload = function(){ //code here } color[1].onload = function(){ //code here } If I had a lot more images, Which I will later in in development, This would be a really inefficient way of checking them all. How would I check them all at the same time?

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  • Infragistics UltraWebTab

    - by user354089
    Im using Infragistcs UltraWebTab. The code is shown below ` <div class="tab-content"> <asp:Panel ID="PnlGeneral" runat="server"> <table width="100%" border="0" cellspacing="0" cellpadding="0" class="tab-list"> <tr> <td style="border-bottom-color: White"> <asp:Label ID="LblErrors" runat="server" CssClass="ErrorMessage1"></asp:Label> <asp:Label ID="LblSuccessMsg" runat="server" CssClass="SuccessMessage1"></asp:Label> </td> </tr> <tr> <td> <table cellpadding="0" cellspacing="0" width="100%" border="0" class="tab-list"> <tr> <th width="205" class="FormLabel1"> Campaign Name <span class="ErrorMessage">*</span> </th> <td width="80%"> <asp:TextBox ID="TxtCampaignName" runat="server" CssClass="TextBox1"></asp:TextBox> </td> </tr> <tr> <th width="205" class="FormLabel1"> CRM Name <span class="ErrorMessage">*</span> </th> <td width="80%"> <asp:TextBox ID="TxtCRMName" runat="server" CssClass="TextBox1"></asp:TextBox> </td> </tr> <tr> <th class="FormLabel1"> Campaign Type <span class="ErrorMessage">*</span> </th> <td> <asp:DropDownList ID="DDLCampaignType" runat="server" CssClass="TextBox1" AutoPostBack="true" Width="117px" OnSelectedIndexChanged="DDLCampaignType_SelectedIndexChanged"> </asp:DropDownList> </td> </tr> <tr visible="false" id="trCompanyRow" runat="server"> <th class="FormLabel1"> Company <span class="ErrorMessage">*</span> </th> <td> <table cellpadding="0" cellspacing="0" border="0" width="100%"> <tr> <td class="style2" style="border-bottom-color: White"> <asp:DropDownList ID="DDLCompany" runat="server" CssClass="TextBox1" Width="117px" OnSelectedIndexChanged="DDLCompany_SelectedIndexChanged"> </asp:DropDownList> </td> <td class="style3" style="border-bottom-color: White"> <asp:LinkButton ID="btnlnknewCompany" runat="server" Style="font-size: 100%;" Text="Add New" OnClick="btnlnknewCompany_Click"></asp:LinkButton> </td> <td style="border-bottom-color: White"> <table cellpadding="0" cellspacing="0" border="0" width="100%" id="tdNewComapny" visible="false" runat="server"> <tr> <td class="style4" style="border-bottom-color: White"> <asp:TextBox ID="txtCompanyName" runat="server"></asp:TextBox> </td> <td style="border-bottom-color: White"> <asp:Button ID="btnCompanyAdd" runat="server" CssClass="btn1" Height="20px" Text="Add" Width="25%" OnClick="btnCompanyAdd_Click" /> </td> </tr> </table> </td> </tr> </table> </td> </tr> <tr id="trBannerImage" runat="server" visible="false"> <th class="FormLabel1"> Banner Image <span class="ErrorMessage">*</span> </th> <td> <asp:FileUpload ID="FileUploadBannerImage" runat="server" ToolTip="Add images for banner" /> </td> </tr> <tr> <th class="FormLabel1"> Start Date <span class="ErrorMessage">*</span> </th> <td> <asp:TextBox ID="TxtStartDate" runat="server" CssClass="TextBox1"></asp:TextBox><rjs:PopCalendar ID="CalStartDate" runat="server" Control="TxtStartDate" Format="dd mm yyyy" ShowErrorMessage="false" /> &nbsp;dd-mm-yyyy </td> </tr> <tr> <th class="FormLabel1"> End Date <span class="ErrorMessage">*</span> </th> <td> <asp:TextBox ID="TxtEndDate" runat="server" CssClass="TextBox1"></asp:TextBox><rjs:PopCalendar ID="CalEndDate" runat="server" Control="TxtEndDate" Format="dd mm yyyy" ShowErrorMessage="false" /> &nbsp;dd-mm-yyyy </td> </tr> <tr> <th class="FormLabel1"> Enabled? </th> <td> <asp:CheckBox ID="ChkEnabled" runat="server" /> </td> </tr> <tr style="border-bottom-color: White" id="tblVerificationFields" visible="false" runat="server"> <th style="border-bottom-color: White"> Company's Verification Fields </th> <td style="border-bottom-color: White"> <table border="0" cellspacing="0" cellpadding="0" class="tab-form" width="100%"> <tr> <td colspan="3" align="center"> <br /> <p> <label style="font-size: 14px; font-weight: bold; text-align: center;"> Select from existing verification fields below</label></p> </td> </tr> <tr> <td colspan="2"> <asp:Repeater ID="RptrVeriFieldsParamType" runat="server"> <HeaderTemplate> <table border="0" cellpadding="0" cellspacing="0" class="tab-grid" style="border: 0px"> <tr> <th> </th> <th> Field Name </th> <th> Type </th> <th> </th> </tr> </HeaderTemplate> <ItemTemplate> <tr> <td style="border-bottom-color: White"> <asp:CheckBox ID="RptrChkVeriFields" runat="server" /> </td> <td style="border-bottom-color: White"> <asp:Label ID="RptrFieldName" runat="server" Text='<%# Eval("FieldName") %>'> </asp:Label> </td> <td style="border-bottom-color: White"> <asp:Label ID="RptrParamterTypeName" runat="server" Text='<%# Eval("PARAMETERTYPENAME") %>'> </asp:Label> </td> <td> <asp:Label ID="RptrHdnFieldId" runat="server" Text='<%# Eval("FIELDID") %>' Visible="false"></asp:Label> </td> </tr> </ItemTemplate> <FooterTemplate> </table> </FooterTemplate> </asp:Repeater> </td> </tr> <tr> <td style="border-bottom-color: White"> </td> </tr> <tr> <td> <table border="0" cellpadding="0" cellspacing="0" width="100%" runat="server"> <tr> <td colspan="6" style="border-bottom-color: White" align="center"> <br /> <p> <label style="font-size: 14px; font-weight: bold; text-align: center; width: 100%;"> Or Add New verification field</label> </p> </td> </tr> <tr id="trVerifcationFields" runat="server" visible="false"> <th style="border-bottom-color: White" width="110px"> <strong>Verification Name</strong> </th> <td style="border-bottom-color: White" width="50px"> <asp:TextBox ID="TxtVeriField" runat="server"> </asp:TextBox> </td> <th style="border-bottom-color: White" width="100px"> <strong>Parameter Type</strong> </th> <td style="border-bottom-color: White" width="100px"> <asp:DropDownList ID="DDLParameterType" runat="server"> </asp:DropDownList> </td> <th> </th> <td align="left" style="border-bottom-color: White"> <asp:Button ID="BtnAddVeriField" runat="server" CssClass="btn1" Height="20px" Text="Add" OnClick="BtnAddVeriField_Click" Width="75%" /> </td> </tr> </table> </td> </tr> </table> </td> </tr> </table> </td> </tr> <tr> <td> <table cellpadding="0" cellspacing="0" width="100%" border="0" class="tab-list"> <tr align="right"> <td> </td> <td align="right" class="tab-list"> <asp:Button runat="server" ID="Next" Visible="true" Text="Next >" CssClass="btn" /> </td> </tr> </table> </td> </tr> </table> </asp:Panel> </div> </ContentTemplate> </igtab:Tab> <igtab:Tab Text="CRM Deals (Step-2)" Key="Tab2"> <ContentTemplate> <div style="clear: both"> </div> <div class="tab-content"> <asp:Panel ID="PnlCRMDeals" runat="server" ScrollBars="Vertical" Height="500px"> <table width="100%" border="0" cellspacing="0" cellpadding="0" class="tab-list"> <tr> <td> <asp:GridView ID="GridDeals" AutoGenerateColumns="False" runat="server" BorderStyle="none" BorderWidth="0" CellPadding="0" CellSpacing="0" GridLines="None" ShowFooter="false" HorizontalAlign="Left" CssClass="tab-grid" Width="100%"> <HeaderStyle CssClass="header" HorizontalAlign="Center" /> <PagerStyle CssClass="pager" /> <AlternatingRowStyle CssClass="odd" /> <Columns> <asp:TemplateField> <ItemStyle Width="5%" /> <ItemTemplate> <asp:CheckBox ID="ChkDeals" runat="server" Visible="true" /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Deal Name"> <ItemStyle Width="25%" /> <ItemTemplate> <asp:Label ID="DealName" runat="server" Text='<%# Eval("DealName") %>' /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Name in CRM"> <ItemTemplate> <asp:Label ID="CRMDealName" runat="server" Text='<%# Eval("CRM_NAME") %>' /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Deal Code"> <ItemTemplate> <asp:Label ID="PartNum" runat="server" Text='<%# Eval("PARTNUM") %>' /> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </td> </tr> </table> </asp:Panel> </div> </ContentTemplate> </igtab:Tab> ` The problem im facing is after the "BtnAddVeriField" add button is clicked the Panel for the next tab gets displayed below the first tab's Panel. Furthermore, that Add button is not displayed as well.

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  • Issues with HLSL and lighting

    - by numerical25
    I am trying figure out whats going on with my HLSL code but I have no way of debugging it cause C++ gives off no errors. The application just closes when I run it. I am trying to add lighting to a 3d plane I made. below is my HLSL. The problem consist when my Pixel shader method returns the struct "outColor" . If I change the return value back to the struct "psInput" , everything goes back to working again. My light vectors and colors are at the top of the fx file // PS_INPUT - input variables to the pixel shader // This struct is created and fill in by the // vertex shader cbuffer Variables { matrix Projection; matrix World; float TimeStep; }; struct PS_INPUT { float4 Pos : SV_POSITION; float4 Color : COLOR0; float3 Normal : TEXCOORD0; float3 ViewVector : TEXCOORD1; }; float specpower = 80.0f; float3 camPos = float3(0.0f, 9.0, -256.0f); float3 DirectLightColor = float3(1.0f, 1.0f, 1.0f); float3 DirectLightVector = float3(0.0f, 0.602f, 0.70f); float3 AmbientLightColor = float3(1.0f, 1.0f, 1.0f); /*************************************** * Lighting functions ***************************************/ /********************************* * CalculateAmbient - * inputs - * vKa material's reflective color * lightColor - the ambient color of the lightsource * output - ambient color *********************************/ float3 CalculateAmbient(float3 vKa, float3 lightColor) { float3 vAmbient = vKa * lightColor; return vAmbient; } /********************************* * CalculateDiffuse - * inputs - * material color * The color of the direct light * the local normal * the vector of the direct light * output - difuse color *********************************/ float3 CalculateDiffuse(float3 baseColor, float3 lightColor, float3 normal, float3 lightVector) { float3 vDiffuse = baseColor * lightColor * saturate(dot(normal, lightVector)); return vDiffuse; } /********************************* * CalculateSpecular - * inputs - * viewVector * the direct light vector * the normal * output - specular highlight *********************************/ float CalculateSpecular(float3 viewVector, float3 lightVector, float3 normal) { float3 vReflect = reflect(lightVector, normal); float fSpecular = saturate(dot(vReflect, viewVector)); fSpecular = pow(fSpecular, specpower); return fSpecular; } /********************************* * LightingCombine - * inputs - * ambient component * diffuse component * specualr component * output - phong color color *********************************/ float3 LightingCombine(float3 vAmbient, float3 vDiffuse, float fSpecular) { float3 vCombined = vAmbient + vDiffuse + fSpecular.xxx; return vCombined; } //////////////////////////////////////////////// // Vertex Shader - Main Function /////////////////////////////////////////////// PS_INPUT VS(float4 Pos : POSITION, float4 Color : COLOR, float3 Normal : NORMAL) { PS_INPUT psInput; float4 newPosition; newPosition = Pos; newPosition.y = sin((newPosition.x * TimeStep) + (newPosition.z / 3.0f)) * 5.0f; // Pass through both the position and the color psInput.Pos = mul(newPosition , Projection ); psInput.Color = Color; psInput.ViewVector = normalize(camPos - psInput.Pos); return psInput; } /////////////////////////////////////////////// // Pixel Shader /////////////////////////////////////////////// //Anthony!!!!!!!!!!! Find out how color works when multiplying them float4 PS(PS_INPUT psInput) : SV_Target { float3 normal = -normalize(psInput.Normal); float3 vAmbient = CalculateAmbient(psInput.Color, AmbientLightColor); float3 vDiffuse = CalculateDiffuse(psInput.Color, DirectLightColor, normal, DirectLightVector); float fSpecular = CalculateSpecular(psInput.ViewVector, DirectLightVector, normal); float4 outColor; outColor.rgb = LightingCombine(vAmbient, vDiffuse, fSpecular); outColor.a = 1.0f; //Below is where the error begins return outColor; } // Define the technique technique10 Render { pass P0 { SetVertexShader( CompileShader( vs_4_0, VS() ) ); SetGeometryShader( NULL ); SetPixelShader( CompileShader( ps_4_0, PS() ) ); } } Below is some of my c++ code. Reason I am showing this is because it is pretty much what creates the surface normals for my shaders to evaluate. for the lighting for(int z=0; z < NUM_ROWS; ++z) { for(int x = 0; x < NUM_COLS; ++x) { int curVertex = x + (z * NUM_VERTSX); indices[curIndex] = curVertex; indices[curIndex + 1] = curVertex + NUM_VERTSX; indices[curIndex + 2] = curVertex + 1; D3DXVECTOR3 v0 = vertices[indices[curIndex]].pos; D3DXVECTOR3 v1 = vertices[indices[curIndex + 1]].pos; D3DXVECTOR3 v2 = vertices[indices[curIndex + 2]].pos; D3DXVECTOR3 normal; D3DXVECTOR3 cross; D3DXVec3Cross(&cross, &D3DXVECTOR3(v2 - v0),&D3DXVECTOR3(v1 - v0)); D3DXVec3Normalize(&normal, &cross); vertices[indices[curIndex]].normal = normal; vertices[indices[curIndex + 1]].normal = normal; vertices[indices[curIndex + 2]].normal = normal; indices[curIndex + 3] = curVertex + 1; indices[curIndex + 4] = curVertex + NUM_VERTSX; indices[curIndex + 5] = curVertex + NUM_VERTSX + 1; v0 = vertices[indices[curIndex + 3]].pos; v1 = vertices[indices[curIndex + 4]].pos; v2 = vertices[indices[curIndex + 5]].pos; D3DXVec3Cross(&cross, &D3DXVECTOR3(v2 - v0),&D3DXVECTOR3(v1 - v0)); D3DXVec3Normalize(&normal, &cross); vertices[indices[curIndex + 3]].normal = normal; vertices[indices[curIndex + 4]].normal = normal; vertices[indices[curIndex + 5]].normal = normal; curIndex += 6; } } and below is my c++ code, in it's entirety. showing the drawing and also calling on the passes #include "MyGame.h" //#include "CubeVector.h" /* This code sets a projection and shows a turning cube. What has been added is the project, rotation and a rasterizer to change the rasterization of the cube. The issue that was going on was something with the effect file which was causing the vertices not to be rendered correctly.*/ typedef struct { ID3D10Effect* pEffect; ID3D10EffectTechnique* pTechnique; //vertex information ID3D10Buffer* pVertexBuffer; ID3D10Buffer* pIndicesBuffer; ID3D10InputLayout* pVertexLayout; UINT numVertices; UINT numIndices; }ModelObject; ModelObject modelObject; // World Matrix D3DXMATRIX WorldMatrix; // View Matrix D3DXMATRIX ViewMatrix; // Projection Matrix D3DXMATRIX ProjectionMatrix; ID3D10EffectMatrixVariable* pProjectionMatrixVariable = NULL; //grid information #define NUM_COLS 16 #define NUM_ROWS 16 #define CELL_WIDTH 32 #define CELL_HEIGHT 32 #define NUM_VERTSX (NUM_COLS + 1) #define NUM_VERTSY (NUM_ROWS + 1) // timer variables LARGE_INTEGER timeStart; LARGE_INTEGER timeEnd; LARGE_INTEGER timerFreq; double currentTime; float anim_rate; // Variable to hold how long since last frame change float lastElaspedFrame = 0; // How long should the frames last float frameDuration = 0.5; bool MyGame::InitDirect3D() { if(!DX3dApp::InitDirect3D()) { return false; } // Get the timer frequency QueryPerformanceFrequency(&timerFreq); float freqSeconds = 1.0f / timerFreq.QuadPart; lastElaspedFrame = 0; D3D10_RASTERIZER_DESC rastDesc; rastDesc.FillMode = D3D10_FILL_WIREFRAME; rastDesc.CullMode = D3D10_CULL_FRONT; rastDesc.FrontCounterClockwise = true; rastDesc.DepthBias = false; rastDesc.DepthBiasClamp = 0; rastDesc.SlopeScaledDepthBias = 0; rastDesc.DepthClipEnable = false; rastDesc.ScissorEnable = false; rastDesc.MultisampleEnable = false; rastDesc.AntialiasedLineEnable = false; ID3D10RasterizerState *g_pRasterizerState; mpD3DDevice->CreateRasterizerState(&rastDesc, &g_pRasterizerState); mpD3DDevice->RSSetState(g_pRasterizerState); // Set up the World Matrix D3DXMatrixIdentity(&WorldMatrix); D3DXMatrixLookAtLH(&ViewMatrix, new D3DXVECTOR3(200.0f, 60.0f, -20.0f), new D3DXVECTOR3(200.0f, 50.0f, 0.0f), new D3DXVECTOR3(0.0f, 1.0f, 0.0f)); // Set up the projection matrix D3DXMatrixPerspectiveFovLH(&ProjectionMatrix, (float)D3DX_PI * 0.5f, (float)mWidth/(float)mHeight, 0.1f, 100.0f); pTimeVariable = NULL; if(!CreateObject()) { return false; } return true; } //These are actions that take place after the clearing of the buffer and before the present void MyGame::GameDraw() { static float rotationAngle = 0.0f; // create the rotation matrix using the rotation angle D3DXMatrixRotationY(&WorldMatrix, rotationAngle); rotationAngle += (float)D3DX_PI * 0.0f; // Set the input layout mpD3DDevice->IASetInputLayout(modelObject.pVertexLayout); // Set vertex buffer UINT stride = sizeof(VertexPos); UINT offset = 0; mpD3DDevice->IASetVertexBuffers(0, 1, &modelObject.pVertexBuffer, &stride, &offset); mpD3DDevice->IASetIndexBuffer(modelObject.pIndicesBuffer, DXGI_FORMAT_R32_UINT, 0); pTimeVariable->SetFloat((float)currentTime); // Set primitive topology mpD3DDevice->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST); // Combine and send the final matrix to the shader D3DXMATRIX finalMatrix = (WorldMatrix * ViewMatrix * ProjectionMatrix); pProjectionMatrixVariable->SetMatrix((float*)&finalMatrix); // make sure modelObject is valid // Render a model object D3D10_TECHNIQUE_DESC techniqueDescription; modelObject.pTechnique->GetDesc(&techniqueDescription); // Loop through the technique passes for(UINT p=0; p < techniqueDescription.Passes; ++p) { modelObject.pTechnique->GetPassByIndex(p)->Apply(0); // draw the cube using all 36 vertices and 12 triangles mpD3DDevice->DrawIndexed(modelObject.numIndices,0,0); } } //Render actually incapsulates Gamedraw, so you can call data before you actually clear the buffer or after you //present data void MyGame::Render() { // Get the start timer count QueryPerformanceCounter(&timeStart); currentTime += anim_rate; DX3dApp::Render(); QueryPerformanceCounter(&timeEnd); anim_rate = ( (float)timeEnd.QuadPart - (float)timeStart.QuadPart ) / timerFreq.QuadPart; } bool MyGame::CreateObject() { VertexPos vertices[NUM_VERTSX * NUM_VERTSY]; for(int z=0; z < NUM_VERTSY; ++z) { for(int x = 0; x < NUM_VERTSX; ++x) { vertices[x + z * NUM_VERTSX].pos.x = (float)x * CELL_WIDTH; vertices[x + z * NUM_VERTSX].pos.z = (float)z * CELL_HEIGHT; vertices[x + z * NUM_VERTSX].pos.y = (float)(rand() % CELL_HEIGHT); vertices[x + z * NUM_VERTSX].color = D3DXVECTOR4(1.0, 0.0f, 0.0f, 0.0f); } } DWORD indices[NUM_VERTSX * NUM_VERTSY * 6]; int curIndex = 0; for(int z=0; z < NUM_ROWS; ++z) { for(int x = 0; x < NUM_COLS; ++x) { int curVertex = x + (z * NUM_VERTSX); indices[curIndex] = curVertex; indices[curIndex + 1] = curVertex + NUM_VERTSX; indices[curIndex + 2] = curVertex + 1; D3DXVECTOR3 v0 = vertices[indices[curIndex]].pos; D3DXVECTOR3 v1 = vertices[indices[curIndex + 1]].pos; D3DXVECTOR3 v2 = vertices[indices[curIndex + 2]].pos; D3DXVECTOR3 normal; D3DXVECTOR3 cross; D3DXVec3Cross(&cross, &D3DXVECTOR3(v2 - v0),&D3DXVECTOR3(v1 - v0)); D3DXVec3Normalize(&normal, &cross); vertices[indices[curIndex]].normal = normal; vertices[indices[curIndex + 1]].normal = normal; vertices[indices[curIndex + 2]].normal = normal; indices[curIndex + 3] = curVertex + 1; indices[curIndex + 4] = curVertex + NUM_VERTSX; indices[curIndex + 5] = curVertex + NUM_VERTSX + 1; v0 = vertices[indices[curIndex + 3]].pos; v1 = vertices[indices[curIndex + 4]].pos; v2 = vertices[indices[curIndex + 5]].pos; D3DXVec3Cross(&cross, &D3DXVECTOR3(v2 - v0),&D3DXVECTOR3(v1 - v0)); D3DXVec3Normalize(&normal, &cross); vertices[indices[curIndex + 3]].normal = normal; vertices[indices[curIndex + 4]].normal = normal; vertices[indices[curIndex + 5]].normal = normal; curIndex += 6; } } //Create Layout D3D10_INPUT_ELEMENT_DESC layout[] = { {"POSITION",0,DXGI_FORMAT_R32G32B32_FLOAT, 0 , 0, D3D10_INPUT_PER_VERTEX_DATA, 0}, {"COLOR",0,DXGI_FORMAT_R32G32B32A32_FLOAT, 0 , 12, D3D10_INPUT_PER_VERTEX_DATA, 0}, {"NORMAL",0,DXGI_FORMAT_R32G32B32A32_FLOAT, 0 , 28, D3D10_INPUT_PER_VERTEX_DATA, 0} }; UINT numElements = (sizeof(layout)/sizeof(layout[0])); modelObject.numVertices = sizeof(vertices)/sizeof(VertexPos); //Create buffer desc D3D10_BUFFER_DESC bufferDesc; bufferDesc.Usage = D3D10_USAGE_DEFAULT; bufferDesc.ByteWidth = sizeof(VertexPos) * modelObject.numVertices; bufferDesc.BindFlags = D3D10_BIND_VERTEX_BUFFER; bufferDesc.CPUAccessFlags = 0; bufferDesc.MiscFlags = 0; D3D10_SUBRESOURCE_DATA initData; initData.pSysMem = vertices; //Create the buffer HRESULT hr = mpD3DDevice->CreateBuffer(&bufferDesc, &initData, &modelObject.pVertexBuffer); if(FAILED(hr)) return false; modelObject.numIndices = sizeof(indices)/sizeof(DWORD); bufferDesc.ByteWidth = sizeof(DWORD) * modelObject.numIndices; bufferDesc.BindFlags = D3D10_BIND_INDEX_BUFFER; initData.pSysMem = indices; hr = mpD3DDevice->CreateBuffer(&bufferDesc, &initData, &modelObject.pIndicesBuffer); if(FAILED(hr)) return false; ///////////////////////////////////////////////////////////////////////////// //Set up fx files LPCWSTR effectFilename = L"effect.fx"; modelObject.pEffect = NULL; hr = D3DX10CreateEffectFromFile(effectFilename, NULL, NULL, "fx_4_0", D3D10_SHADER_ENABLE_STRICTNESS, 0, mpD3DDevice, NULL, NULL, &modelObject.pEffect, NULL, NULL); if(FAILED(hr)) return false; pProjectionMatrixVariable = modelObject.pEffect->GetVariableByName("Projection")->AsMatrix(); pTimeVariable = modelObject.pEffect->GetVariableByName("TimeStep")->AsScalar(); //Dont sweat the technique. Get it! LPCSTR effectTechniqueName = "Render"; modelObject.pTechnique = modelObject.pEffect->GetTechniqueByName(effectTechniqueName); if(modelObject.pTechnique == NULL) return false; //Create Vertex layout D3D10_PASS_DESC passDesc; modelObject.pTechnique->GetPassByIndex(0)->GetDesc(&passDesc); hr = mpD3DDevice->CreateInputLayout(layout, numElements, passDesc.pIAInputSignature, passDesc.IAInputSignatureSize, &modelObject.pVertexLayout); if(FAILED(hr)) return false; return true; }

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  • black and white pages not recognized by printer

    - by user46627
    I have a document which has color on about 25% of its pages. When I print it in the copy shop, the printer's technically supposed to recognize the b/w pages. However, all pages are registered as colored, i.e. the pages are color-enabled pages which happen to not have any colors on them (but I'm paying for the color-enabled-ness). Regrettably, the staff have to charge me for color because the printer's leased and they have to pay for color pages, so showing them that there's no color doesn't help me. What are possible sources for b/w pages showing up like that?

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  • How do I add color syntax highlighting to GNU emacs?

    - by Alex Reynolds
    I have two versions of emacs available to me on a locked workstation: $ /usr/local/bin/emacs --version GNU Emacs 22.3.1 $ /usr/bin/emacs --version GNU Emacs 21.4.1 In both cases, my terminal type is xterm when I run either version of emacs. When I run the v21 version of emacs, I get syntax coloring for Perl, HTML, and other modes. When I run the v22 version, I do not get syntax coloring. I would like to migrate from the v21 version because the combination of v21 emacs, GNOME Terminal and GNU Screen is eating Ctrl-arrow key chords, which prevents me from moving quickly between words. (OS X Terminal and GNU Screen do not have this issue.) The v22 version allows use of Ctrl-arrow key combinations with GNOME Terminal and GNU Screen. How do I fix the v22 version (or ask my sys admin to fix) so that it once again highlights syntax and allows me to use Ctrl-arrow key combinations?

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  • Convert color photos of documents to good black-and-white images?

    - by Norman Ramsey
    Since I don't have a copier or scanner, I'm using an 8 megapixel camera to copy documents. This works pretty well except they need a lot of processing afterward. I'd like to get from a photo to a bitmap, but using djpeg -grayscale -pnm photo.jpg | pgmtopbm -threshold -value XXX does not work so well, for two reasons: It's hard to guess what XXX should be, and XXX is different for different photos. Illumination varies, and sometimes a single threshold isn't what's right for the image. How can I do better? The ideal solution will be fully automatic command-line program that I can run on Linux. (I have already written a program to remove dark pixels from the edges of images.)

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  • Where is a reputable place to buy ink refills for my color laser printer?

    - by FooBook
    I was looking around for a place to buy a refill kit for my laser printer. Of course, there are thousands of websites that are selling these kits. The problem is that I can't tell which one is a good one to buy from. How can I tell if the store has a good reputation. I don't want to pay, and then not receive the item. This has happened to me before (IvySkin). Or get conned some other way. One place I found is printerinkcartridge.us. But again, I can't find any independent information from people that they have successfully ordered products from there, and that they received what they expected. Are there any reliable sites you can suggest where I may order a kit from? Is the one I found good enough? Thanks guys.

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  • Color drop down in Excel cell (with no text)? e.g. bgcolor = Red-Green-Amber-unknown

    - by adolf garlic
    I have an Excel sheet that I'm using to keep track of the status of certain things. I want to have a column which consists of cells containing a repeated drop down that allows you to select (as background) red amber green unknown I don't want any text in this cell, I just want a coloured block. Is this possible? I've tried playing around with data-validation-list (based on range containing all of said colours but to no avail)

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  • How do I find all text with particular background color?

    - by Dave M G
    I have a LibreOffice Writer document that has undergone a process of editing, and sections of the text that needed to be rewritten were highlighted in yellow. As I fixed those sections, I removed the yellow highlight. Now, I want to make sure there are no remaining areas of highlighted text that have not been fixed or possibly the highlight was not removed. It's many hundreds of pages, so a manual scan is unfeasible. Also, it might be that one space or one character got accidentally left highlighted, and I want to ensure I've accounted for them all. How can I search the document to find all instances where text has been highlighted?

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  • what TERM to use to get rid of color escape codes?

    - by slivu
    Is there a way to get rid of escape codes in terminal output? Say even if the script are sending that codes they are ignored by terminal and text displayed as is, without colors, bolds etc. I need to display terminal output on a HTML page. For now i'm using javascript to remove escape codes, but it becomes clunky cause i receive output by chars, and have to wait until all content received then update it, leading in weird effects.

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  • Parallelism in .NET – Part 3, Imperative Data Parallelism: Early Termination

    - by Reed
    Although simple data parallelism allows us to easily parallelize many of our iteration statements, there are cases that it does not handle well.  In my previous discussion, I focused on data parallelism with no shared state, and where every element is being processed exactly the same. Unfortunately, there are many common cases where this does not happen.  If we are dealing with a loop that requires early termination, extra care is required when parallelizing. Often, while processing in a loop, once a certain condition is met, it is no longer necessary to continue processing.  This may be a matter of finding a specific element within the collection, or reaching some error case.  The important distinction here is that, it is often impossible to know until runtime, what set of elements needs to be processed. In my initial discussion of data parallelism, I mentioned that this technique is a candidate when you can decompose the problem based on the data involved, and you wish to apply a single operation concurrently on all of the elements of a collection.  This covers many of the potential cases, but sometimes, after processing some of the elements, we need to stop processing. As an example, lets go back to our previous Parallel.ForEach example with contacting a customer.  However, this time, we’ll change the requirements slightly.  In this case, we’ll add an extra condition – if the store is unable to email the customer, we will exit gracefully.  The thinking here, of course, is that if the store is currently unable to email, the next time this operation runs, it will handle the same situation, so we can just skip our processing entirely.  The original, serial case, with this extra condition, might look something like the following: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) break; customer.LastEmailContact = DateTime.Now; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re processing our loop, but at any point, if we fail to send our email successfully, we just abandon this process, and assume that it will get handled correctly the next time our routine is run.  If we try to parallelize this using Parallel.ForEach, as we did previously, we’ll run into an error almost immediately: the break statement we’re using is only valid when enclosed within an iteration statement, such as foreach.  When we switch to Parallel.ForEach, we’re no longer within an iteration statement – we’re a delegate running in a method. This needs to be handled slightly differently when parallelized.  Instead of using the break statement, we need to utilize a new class in the Task Parallel Library: ParallelLoopState.  The ParallelLoopState class is intended to allow concurrently running loop bodies a way to interact with each other, and provides us with a way to break out of a loop.  In order to use this, we will use a different overload of Parallel.ForEach which takes an IEnumerable<T> and an Action<T, ParallelLoopState> instead of an Action<T>.  Using this, we can parallelize the above operation by doing: Parallel.ForEach(customers, (customer, parallelLoopState) => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) parallelLoopState.Break(); else customer.LastEmailContact = DateTime.Now; } }); There are a couple of important points here.  First, we didn’t actually instantiate the ParallelLoopState instance.  It was provided directly to us via the Parallel class.  All we needed to do was change our lambda expression to reflect that we want to use the loop state, and the Parallel class creates an instance for our use.  We also needed to change our logic slightly when we call Break().  Since Break() doesn’t stop the program flow within our block, we needed to add an else case to only set the property in customer when we succeeded.  This same technique can be used to break out of a Parallel.For loop. That being said, there is a huge difference between using ParallelLoopState to cause early termination and to use break in a standard iteration statement.  When dealing with a loop serially, break will immediately terminate the processing within the closest enclosing loop statement.  Calling ParallelLoopState.Break(), however, has a very different behavior. The issue is that, now, we’re no longer processing one element at a time.  If we break in one of our threads, there are other threads that will likely still be executing.  This leads to an important observation about termination of parallel code: Early termination in parallel routines is not immediate.  Code will continue to run after you request a termination. This may seem problematic at first, but it is something you just need to keep in mind while designing your routine.  ParallelLoopState.Break() should be thought of as a request.  We are telling the runtime that no elements that were in the collection past the element we’re currently processing need to be processed, and leaving it up to the runtime to decide how to handle this as gracefully as possible.  Although this may seem problematic at first, it is a good thing.  If the runtime tried to immediately stop processing, many of our elements would be partially processed.  It would be like putting a return statement in a random location throughout our loop body – which could have horrific consequences to our code’s maintainability. In order to understand and effectively write parallel routines, we, as developers, need a subtle, but profound shift in our thinking.  We can no longer think in terms of sequential processes, but rather need to think in terms of requests to the system that may be handled differently than we’d first expect.  This is more natural to developers who have dealt with asynchronous models previously, but is an important distinction when moving to concurrent programming models. As an example, I’ll discuss the Break() method.  ParallelLoopState.Break() functions in a way that may be unexpected at first.  When you call Break() from a loop body, the runtime will continue to process all elements of the collection that were found prior to the element that was being processed when the Break() method was called.  This is done to keep the behavior of the Break() method as close to the behavior of the break statement as possible. We can see the behavior in this simple code: var collection = Enumerable.Range(0, 20); var pResult = Parallel.ForEach(collection, (element, state) => { if (element > 10) { Console.WriteLine("Breaking on {0}", element); state.Break(); } Console.WriteLine(element); }); If we run this, we get a result that may seem unexpected at first: 0 2 1 5 6 3 4 10 Breaking on 11 11 Breaking on 12 12 9 Breaking on 13 13 7 8 Breaking on 15 15 What is occurring here is that we loop until we find the first element where the element is greater than 10.  In this case, this was found, the first time, when one of our threads reached element 11.  It requested that the loop stop by calling Break() at this point.  However, the loop continued processing until all of the elements less than 11 were completed, then terminated.  This means that it will guarantee that elements 9, 7, and 8 are completed before it stops processing.  You can see our other threads that were running each tried to break as well, but since Break() was called on the element with a value of 11, it decides which elements (0-10) must be processed. If this behavior is not desirable, there is another option.  Instead of calling ParallelLoopState.Break(), you can call ParallelLoopState.Stop().  The Stop() method requests that the runtime terminate as soon as possible , without guaranteeing that any other elements are processed.  Stop() will not stop the processing within an element, so elements already being processed will continue to be processed.  It will prevent new elements, even ones found earlier in the collection, from being processed.  Also, when Stop() is called, the ParallelLoopState’s IsStopped property will return true.  This lets longer running processes poll for this value, and return after performing any necessary cleanup. The basic rule of thumb for choosing between Break() and Stop() is the following. Use ParallelLoopState.Stop() when possible, since it terminates more quickly.  This is particularly useful in situations where you are searching for an element or a condition in the collection.  Once you’ve found it, you do not need to do any other processing, so Stop() is more appropriate. Use ParallelLoopState.Break() if you need to more closely match the behavior of the C# break statement. Both methods behave differently than our C# break statement.  Unfortunately, when parallelizing a routine, more thought and care needs to be put into every aspect of your routine than you may otherwise expect.  This is due to my second observation: Parallelizing a routine will almost always change its behavior. This sounds crazy at first, but it’s a concept that’s so simple its easy to forget.  We’re purposely telling the system to process more than one thing at the same time, which means that the sequence in which things get processed is no longer deterministic.  It is easy to change the behavior of your routine in very subtle ways by introducing parallelism.  Often, the changes are not avoidable, even if they don’t have any adverse side effects.  This leads to my final observation for this post: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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  • Parallelism in .NET – Part 7, Some Differences between PLINQ and LINQ to Objects

    - by Reed
    In my previous post on Declarative Data Parallelism, I mentioned that PLINQ extends LINQ to Objects to support parallel operations.  Although nearly all of the same operations are supported, there are some differences between PLINQ and LINQ to Objects.  By introducing Parallelism to our declarative model, we add some extra complexity.  This, in turn, adds some extra requirements that must be addressed. In order to illustrate the main differences, and why they exist, let’s begin by discussing some differences in how the two technologies operate, and look at the underlying types involved in LINQ to Objects and PLINQ . LINQ to Objects is mainly built upon a single class: Enumerable.  The Enumerable class is a static class that defines a large set of extension methods, nearly all of which work upon an IEnumerable<T>.  Many of these methods return a new IEnumerable<T>, allowing the methods to be chained together into a fluent style interface.  This is what allows us to write statements that chain together, and lead to the nice declarative programming model of LINQ: double min = collection .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Other LINQ variants work in a similar fashion.  For example, most data-oriented LINQ providers are built upon an implementation of IQueryable<T>, which allows the database provider to turn a LINQ statement into an underlying SQL query, to be performed directly on the remote database. PLINQ is similar, but instead of being built upon the Enumerable class, most of PLINQ is built upon a new static class: ParallelEnumerable.  When using PLINQ, you typically begin with any collection which implements IEnumerable<T>, and convert it to a new type using an extension method defined on ParallelEnumerable: AsParallel().  This method takes any IEnumerable<T>, and converts it into a ParallelQuery<T>, the core class for PLINQ.  There is a similar ParallelQuery class for working with non-generic IEnumerable implementations. This brings us to our first subtle, but important difference between PLINQ and LINQ – PLINQ always works upon specific types, which must be explicitly created. Typically, the type you’ll use with PLINQ is ParallelQuery<T>, but it can sometimes be a ParallelQuery or an OrderedParallelQuery<T>.  Instead of dealing with an interface, implemented by an unknown class, we’re dealing with a specific class type.  This works seamlessly from a usage standpoint – ParallelQuery<T> implements IEnumerable<T>, so you can always “switch back” to an IEnumerable<T>.  The difference only arises at the beginning of our parallelization.  When we’re using LINQ, and we want to process a normal collection via PLINQ, we need to explicitly convert the collection into a ParallelQuery<T> by calling AsParallel().  There is an important consideration here – AsParallel() does not need to be called on your specific collection, but rather any IEnumerable<T>.  This allows you to place it anywhere in the chain of methods involved in a LINQ statement, not just at the beginning.  This can be useful if you have an operation which will not parallelize well or is not thread safe.  For example, the following is perfectly valid, and similar to our previous examples: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); However, if SomeOperation() is not thread safe, we could just as easily do: double min = collection .Select(item => item.SomeOperation()) .AsParallel() .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); In this case, we’re using standard LINQ to Objects for the Select(…) method, then converting the results of that map routine to a ParallelQuery<T>, and processing our filter (the Where method) and our aggregation (the Min method) in parallel. PLINQ also provides us with a way to convert a ParallelQuery<T> back into a standard IEnumerable<T>, forcing sequential processing via standard LINQ to Objects.  If SomeOperation() was thread-safe, but PerformComputation() was not thread-safe, we would need to handle this by using the AsEnumerable() method: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .AsEnumerable() .Min(item => item.PerformComputation()); Here, we’re converting our collection into a ParallelQuery<T>, doing our map operation (the Select(…) method) and our filtering in parallel, then converting the collection back into a standard IEnumerable<T>, which causes our aggregation via Min() to be performed sequentially. This could also be written as two statements, as well, which would allow us to use the language integrated syntax for the first portion: var tempCollection = from item in collection.AsParallel() let e = item.SomeOperation() where (e.SomeProperty > 6 && e.SomeProperty < 24) select e; double min = tempCollection.AsEnumerable().Min(item => item.PerformComputation()); This allows us to use the standard LINQ style language integrated query syntax, but control whether it’s performed in parallel or serial by adding AsParallel() and AsEnumerable() appropriately. The second important difference between PLINQ and LINQ deals with order preservation.  PLINQ, by default, does not preserve the order of of source collection. This is by design.  In order to process a collection in parallel, the system needs to naturally deal with multiple elements at the same time.  Maintaining the original ordering of the sequence adds overhead, which is, in many cases, unnecessary.  Therefore, by default, the system is allowed to completely change the order of your sequence during processing.  If you are doing a standard query operation, this is usually not an issue.  However, there are times when keeping a specific ordering in place is important.  If this is required, you can explicitly request the ordering be preserved throughout all operations done on a ParallelQuery<T> by using the AsOrdered() extension method.  This will cause our sequence ordering to be preserved. For example, suppose we wanted to take a collection, perform an expensive operation which converts it to a new type, and display the first 100 elements.  In LINQ to Objects, our code might look something like: // Using IEnumerable<SourceClass> collection IEnumerable<ResultClass> results = collection .Select(e => e.CreateResult()) .Take(100); If we just converted this to a parallel query naively, like so: IEnumerable<ResultClass> results = collection .AsParallel() .Select(e => e.CreateResult()) .Take(100); We could very easily get a very different, and non-reproducable, set of results, since the ordering of elements in the input collection is not preserved.  To get the same results as our original query, we need to use: IEnumerable<ResultClass> results = collection .AsParallel() .AsOrdered() .Select(e => e.CreateResult()) .Take(100); This requests that PLINQ process our sequence in a way that verifies that our resulting collection is ordered as if it were processed serially.  This will cause our query to run slower, since there is overhead involved in maintaining the ordering.  However, in this case, it is required, since the ordering is required for correctness. PLINQ is incredibly useful.  It allows us to easily take nearly any LINQ to Objects query and run it in parallel, using the same methods and syntax we’ve used previously.  There are some important differences in operation that must be considered, however – it is not a free pass to parallelize everything.  When using PLINQ in order to parallelize your routines declaratively, the same guideline I mentioned before still applies: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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  • Parallelism in .NET – Part 9, Configuration in PLINQ and TPL

    - by Reed
    Parallel LINQ and the Task Parallel Library contain many options for configuration.  Although the default configuration options are often ideal, there are times when customizing the behavior is desirable.  Both frameworks provide full configuration support. When working with Data Parallelism, there is one primary configuration option we often need to control – the number of threads we want the system to use when parallelizing our routine.  By default, PLINQ and the TPL both use the ThreadPool to schedule tasks.  Given the major improvements in the ThreadPool in CLR 4, this default behavior is often ideal.  However, there are times that the default behavior is not appropriate.  For example, if you are working on multiple threads simultaneously, and want to schedule parallel operations from within both threads, you might want to consider restricting each parallel operation to using a subset of the processing cores of the system.  Not doing this might over-parallelize your routine, which leads to inefficiencies from having too many context switches. In the Task Parallel Library, configuration is handled via the ParallelOptions class.  All of the methods of the Parallel class have an overload which accepts a ParallelOptions argument. We configure the Parallel class by setting the ParallelOptions.MaxDegreeOfParallelism property.  For example, let’s revisit one of the simple data parallel examples from Part 2: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re looping through an image, and calling a method on each pixel in the image.  If this was being done on a separate thread, and we knew another thread within our system was going to be doing a similar operation, we likely would want to restrict this to using half of the cores on the system.  This could be accomplished easily by doing: var options = new ParallelOptions(); options.MaxDegreeOfParallelism = Math.Max(Environment.ProcessorCount / 2, 1); Parallel.For(0, pixelData.GetUpperBound(0), options, row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Now, we’re restricting this routine to using no more than half the cores in our system.  Note that I included a check to prevent a single core system from supplying zero; without this check, we’d potentially cause an exception.  I also did not hard code a specific value for the MaxDegreeOfParallelism property.  One of our goals when parallelizing a routine is allowing it to scale on better hardware.  Specifying a hard-coded value would contradict that goal. Parallel LINQ also supports configuration, and in fact, has quite a few more options for configuring the system.  The main configuration option we most often need is the same as our TPL option: we need to supply the maximum number of processing threads.  In PLINQ, this is done via a new extension method on ParallelQuery<T>: ParallelEnumerable.WithDegreeOfParallelism. Let’s revisit our declarative data parallelism sample from Part 6: double min = collection.AsParallel().Min(item => item.PerformComputation()); Here, we’re performing a computation on each element in the collection, and saving the minimum value of this operation.  If we wanted to restrict this to a limited number of threads, we would add our new extension method: int maxThreads = Math.Max(Environment.ProcessorCount / 2, 1); double min = collection .AsParallel() .WithDegreeOfParallelism(maxThreads) .Min(item => item.PerformComputation()); This automatically restricts the PLINQ query to half of the threads on the system. PLINQ provides some additional configuration options.  By default, PLINQ will occasionally revert to processing a query in parallel.  This occurs because many queries, if parallelized, typically actually cause an overall slowdown compared to a serial processing equivalent.  By analyzing the “shape” of the query, PLINQ often decides to run a query serially instead of in parallel.  This can occur for (taken from MSDN): Queries that contain a Select, indexed Where, indexed SelectMany, or ElementAt clause after an ordering or filtering operator that has removed or rearranged original indices. Queries that contain a Take, TakeWhile, Skip, SkipWhile operator and where indices in the source sequence are not in the original order. Queries that contain Zip or SequenceEquals, unless one of the data sources has an originally ordered index and the other data source is indexable (i.e. an array or IList(T)). Queries that contain Concat, unless it is applied to indexable data sources. Queries that contain Reverse, unless applied to an indexable data source. If the specific query follows these rules, PLINQ will run the query on a single thread.  However, none of these rules look at the specific work being done in the delegates, only at the “shape” of the query.  There are cases where running in parallel may still be beneficial, even if the shape is one where it typically parallelizes poorly.  In these cases, you can override the default behavior by using the WithExecutionMode extension method.  This would be done like so: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .Select(i => i.PerformComputation()) .Reverse(); Here, the default behavior would be to not parallelize the query unless collection implemented IList<T>.  We can force this to run in parallel by adding the WithExecutionMode extension method in the method chain. Finally, PLINQ has the ability to configure how results are returned.  When a query is filtering or selecting an input collection, the results will need to be streamed back into a single IEnumerable<T> result.  For example, the method above returns a new, reversed collection.  In this case, the processing of the collection will be done in parallel, but the results need to be streamed back to the caller serially, so they can be enumerated on a single thread. This streaming introduces overhead.  IEnumerable<T> isn’t designed with thread safety in mind, so the system needs to handle merging the parallel processes back into a single stream, which introduces synchronization issues.  There are two extremes of how this could be accomplished, but both extremes have disadvantages. The system could watch each thread, and whenever a thread produces a result, take that result and send it back to the caller.  This would mean that the calling thread would have access to the data as soon as data is available, which is the benefit of this approach.  However, it also means that every item is introducing synchronization overhead, since each item needs to be merged individually. On the other extreme, the system could wait until all of the results from all of the threads were ready, then push all of the results back to the calling thread in one shot.  The advantage here is that the least amount of synchronization is added to the system, which means the query will, on a whole, run the fastest.  However, the calling thread will have to wait for all elements to be processed, so this could introduce a long delay between when a parallel query begins and when results are returned. The default behavior in PLINQ is actually between these two extremes.  By default, PLINQ maintains an internal buffer, and chooses an optimal buffer size to maintain.  Query results are accumulated into the buffer, then returned in the IEnumerable<T> result in chunks.  This provides reasonably fast access to the results, as well as good overall throughput, in most scenarios. However, if we know the nature of our algorithm, we may decide we would prefer one of the other extremes.  This can be done by using the WithMergeOptions extension method.  For example, if we know that our PerformComputation() routine is very slow, but also variable in runtime, we may want to retrieve results as they are available, with no bufferring.  This can be done by changing our above routine to: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.NotBuffered) .Select(i => i.PerformComputation()) .Reverse(); On the other hand, if are already on a background thread, and we want to allow the system to maximize its speed, we might want to allow the system to fully buffer the results: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.FullyBuffered) .Select(i => i.PerformComputation()) .Reverse(); Notice, also, that you can specify multiple configuration options in a parallel query.  By chaining these extension methods together, we generate a query that will always run in parallel, and will always complete before making the results available in our IEnumerable<T>.

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