Search Results

Search found 266 results on 11 pages for 'multiplication'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 2/11 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11  | Next Page >

  • Notebook display problem (multiplication)

    - by SubniC
    Hi, I'm having some troubles with the display of a LG E500 notebook. The thing is that without any known reason the display starts to show the screen divided in eigth parts and each part show the display image as if I had a matrix of eigth displays :) I thought it could be some kind of refresh rate problem or driver related, but it is happening at boot-up as well and the BIOS. I got the computer completely unassambled yesterday and I check all the wires and connectors looking for something broken or unconected, but without luck... You can see a picture here of the problem (sorry for the low quality, but I think it illustrate the problem. EDIT 1: I uploaded a new pictrue, here you cans ee the problem better :) There are three horizontal lines that you can see just between the windows. You can see the grey line at the first moment you turn on the computer and the after the duplicated screens show up just like if they where arranged over a grid (over the horizontal lines...) I hope it makes any sense. Do you know what could be happening? or can you tell me what would you do? Thank you very much for your help.

    Read the article

  • Arrays multiplication

    - by mariO
    How to write arrayt multiplication (multiplicating two matrieces ie 3x3) of arrays of known size in c++ ? What will be the difference using pointers and reference ?

    Read the article

  • iphone integer multiplication

    - by Rob
    I don't understand why this doesn't work: [abc = ([def intValue] - 71) * 6]; '*' should be the viable way of doing multiplication and 'abc' is defined as an NSInteger. ('def' is an NSString)

    Read the article

  • Question with R. Element wise multiplication, addition, and division with 2 data.frames with varying

    - by Michael
    I have a various data.frames with columns of the same length where I am trying to multiple 2 rows together element-wise and then sum this up. For example, below are two vectors I would like to perform this operation with. > a.1[186,] q01_a q01_b q01_c q01_d q01_e q01_f q01_g q01_h q01_i q01_j q01_k q01_l q01_m 3 3 3 3 2 2 2 3 1 NA NA 2 2 and > u.1[186,] q04_avl_a q04_avl_b q04_avl_c q04_avl_d q04_avl_e q04_avl_f q04_avl_g q04_avl_h q04_avl_i q04_avl_j q04_avl_k q04_avl_l q04_avl_m 4 2 3 4 3 4 4 4 3 4 3 3 3` The issue is that various rows have varying numbers of NA's. What I would like to do is skip the multiplication with any missing values ( the 10th and 11th position from my above example), and then after the addition divide by the number of elements that were multiplied (11 from the above example). Most rows are complete and would just be multiplied by 13. Thank you!

    Read the article

  • Mat matrix multiplication, openCV?

    - by facebook-1593205594
    I initialized two Mat images as: Mat ft=Mat::zeros(src.rows,src.cols,CV_32FC1),h=Mat::zeros(src.rows,src.cols,CV_32FC1); and then i have some calculations: ft has fourier transform stored for an image, and h has matrix for Laplacian filtering in fourier domain.......they both have same dimensions, and then i did multiplication of them using both h*ft and gemm(h,ft,1,NULL,0,temp); function call but while executing it shows some problems..... it reads like this: opencv error assertion failed (some long code and at last says something about gemm in ....matmul.cpp)......termination called after throwing exception of 'cv::exception'

    Read the article

  • For...Next Loop Multiplication Table to Start on 0

    - by nikl91
    I have my For...Next loop with a multiplication table working just fine, but I want the top left box to start at 0 and move on from there. Giving me some trouble. dim mult mult = "" For row = 1 to 50 mult = mult & "" For col= 1 to 20 mult = mult & "" & row * col & "" Next mult = mult & "" Next mult = mult & "" response.write mult This is what I have so far. Any suggestions?

    Read the article

  • For...Next Loop Multiplication Table to Start on 0

    - by nikl91
    I have my For...Next loop with a multiplication table working just fine, but I want the top left box to start at 0 and move on from there. Giving me some trouble. dim mult mult = "<table width = ""100%"" border= ""1"" >" For row = 1 to 50 mult = mult & "<tr align = ""center"" >" For col= 1 to 20 mult = mult & "<td>" & row * col & "</td>" Next mult = mult & "</tr>" Next mult = mult & "</table>" response.write mult This is what I have so far. Any suggestions?

    Read the article

  • Basic C++ code for multiplication of 2 matrix or vectors (C++ beginner)

    - by Ice
    I am a new C++ user and I am also doing a major in Maths so thought I would try implement a simple calculator. I got some code off the internet and now I just need help to multiply elements of 2 matrices or vectors. Matrixf multiply(Matrixf const& left, Matrixf const& right) { // error check if (left.ncols() != right.nrows()) { throw std::runtime_error("Unable to multiply: matrix dimensions not agree."); } /* I have all the other part of the code for matrix*/ /** Now I am not sure how to implement multiplication of vector or matrix.**/ Matrixf ret(1, 1); return ret; }

    Read the article

  • Segmentation fault while matrix multiplication using openMp?

    - by harshit
    My matrix multiplication code is int matMul(int ld, double** matrix) { //local variables initialize omp_set_num_threads(nthreads); #pragma omp parallel private(tid,diag,ld) shared(i,j,k,matrix) { /* Obtain and print thread id */ tid = omp_get_thread_num(); for ( k=0; k<ld; k++) { if (matrix[k][k] == 0.0) { error = 1; return error; } diag = 1.0 / matrix[k][k]; #pragma omp for for ( i=k+1; i < ld; i++) { matrix[i][k] = diag * matrix[i][k]; } for ( j=k+1; j<ld; j++) { for ( i=k+1; i<ld; i++) { matrix[i][j] = matrix[i][j] - matrix[i][k] * matrix[k][j]; } } } } return error; } I assume that it is because of matrix object only but why will it be null even though it is passed as a parameter..

    Read the article

  • Precision error on matrix multiplication

    - by Wam
    Hello all, Coding a matrix multiplication in my program, I get precision errors (inaccurate results for large matrices). Here's my code. The current object has data stored in a flattened array, row after row. Other matrix B has data stored in a flattened array, column after column (so I can use pointer arithmetic). protected double[,] multiply (IMatrix B) { int columns = B.columns; int rows = Rows; int size = Columns; double[,] result = new double[rows,columns]; for (int row = 0; row < rows; row++) { for (int col = 0; col < columns; col++) { unsafe { fixed (float* ptrThis = data) fixed (float* ptrB = B.Data) { float* mePtr = ptrThis + row*rows; float* bPtr = ptrB + col*columns; double value = 0.0; for (int i = 0; i < size; i++) { value += *(mePtr++) * *(bPtr++); } result[row, col] = value; } } } } } Actually, the code is a bit more complicated : I do the multiply thing for several chunks (so instead of having i from 0 to size, I go from localStart to localStop), then sum up the resulting matrices. My problem : for a big matrix I get precision error : NUnit.Framework.AssertionException: Error at (0,1) expected: <6.4209571409444209E+18> but was: <6.4207619776304906E+18> Any idea ?

    Read the article

  • OpenCL Matrix Multiplication - Getting wrong answer

    - by Yash
    here's a simple OpenCL Matrix Multiplication kernel which is driving me crazy: __kernel void matrixMul( __global int* C, __global int* A, __global int* B, int wA, int wB){ int row = get_global_id(1); //2D Threas ID x int col = get_global_id(0); //2D Threas ID y //Perform dot-product accumulated into value int value; for ( int k = 0; k < wA; k++ ){ value += A[row*wA + k] * B[k*wB+col]; } C[row*wA+col] = value; //Write to the device memory } Where (inputs) A = [72 45 75 61] B = [26 53 46 76] Output I am getting: C = [3942 7236 3312 5472] But the output should be: C = [3943 7236 4756 8611] The problem I am facing here is that for any dimension array the elements of the first row of the resulting matrix is correct. The elements of all the other rows of the resulting matrix is wrong. By the way I am using pyopencl. I don't know what I mistake I am doing here. I have spent the entire day with no luck. Please help me with this

    Read the article

  • Efficient Multiplication of Varying-Length #s [Conceptual]

    - by Milan Patel
    Write the pseudocode of an algorithm that takes in two arbitrary length numbers (provided as strings), and computes the product of these numbers. Use an efficient procedure for multiplication of large numbers of arbitrary length. Analyze the efficiency of your algorithm. I decided to take the (semi) easy way out and use the Russian Peasant Algorithm. It works like this: a * b = a/2 * 2b if a is even a * b = (a-1)/2 * 2b + a if a is odd My pseudocode is: rpa(x, y){ if x is 1 return y if x is even return rpa(x/2, 2y) if x is odd return rpa((x-1)/2, 2y) + y } I have 3 questions: Is this efficient for arbitrary length numbers? I implemented it in C and tried varying length numbers. The run-time in was near-instant in all cases so it's hard to tell empirically... Can I apply the Master's Theorem to understand the complexity...? a = # subproblems in recursion = 1 (max 1 recursive call across all states) n / b = size of each subproblem = n / 1 - b = 1 (problem doesn't change size...?) f(n^d) = work done outside recursive calls = 1 - d = 0 (the addition when a is odd) a = 1, b^d = 1, a = b^d - complexity is in n^d*log(n) = log(n) this makes sense logically since we are halving the problem at each step, right? What might my professor mean by providing arbitrary length numbers "as strings". Why do that? Many thanks in advance

    Read the article

  • array multiplication task

    - by toby
    I am tying to get around how you will multiply the values in 2 arrays (as an input) to get an output. The problem I have is the how to increment the loops to achieve the task shown below #include <iostream> using namespace std; main () { int* filter1, *signal,fsize1=0,fsize2=0,i=0; cout<<" enter size of filter and signal"<<endl; cin>> fsize1 >> fsize2; filter1= new int [fsize1]; signal= new int [fsize2]; cout<<" enter filter values"<<endl; for (i=0;i<fsize1;i++) cin>>filter1[i]; cout<<" enter signal values"<<endl; for (i=0;i<fsize2;i++) cin>>signal[i]; /* the two arrays should be filled by users but use the arrays below for test int array1[6]={2,4,6,7,8,9}; int array2[3]={1,2,3}; The output array should be array3[9]={1*2,(1*4+2*2),(1*6+2*4+3*2),........,(1*9+2*8+3*7),(2*9+3*8),3*9} */ return 0; } This is part of a bigger task concerning filter of a sampled signal but it is this multiplication that i cant get done.

    Read the article

  • La multiplication anarchique des applications est un problème majeur pour 74 % des DSI, les applications sous-utilisées aussi, d'après HP

    La multiplication anarchique des applications est un problème majeur Pour 74% des DSI, les applications sous-utilisées aussi, d'après HP HP vient de publier une étude qui montre que la multiplication anarchique des applications est un problème majeur des organisations européennes. Un problème qui accapare, pour la maintenance, des ressources qui pourraient être mieux consacrées et allouées à l'innovation. Deuxième conclusion de ce rapport, un DSI européen sur deux estime être empêché par les métiers de conduire des initiatives de modernisation des applications, par crainte des risques associés au changement. D'après cette étude, les portefeuilles applicatifs sont en...

    Read the article

  • 5x5 matrix multiplication in C

    - by Rick
    I am stuck on this problem in my homework. I've made it this far and am sure the problem is in my three for loops. The question directly says to use 3 for loops so I know this is probably just a logic error. #include<stdio.h> void matMult(int A[][5],int B[][5],int C[][5]); int printMat_5x5(int A[5][5]); int main() { int A[5][5] = {{1,2,3,4,6}, {6,1,5,3,8}, {2,6,4,9,9}, {1,3,8,3,4}, {5,7,8,2,5}}; int B[5][5] = {{3,5,0,8,7}, {2,2,4,8,3}, {0,2,5,1,2}, {1,4,0,5,1}, {3,4,8,2,3}}; int C[5][5] = {0}; matMult(A,B,C); printMat_5x5(A); printf("\n"); printMat_5x5(B); printf("\n"); printMat_5x5(C); return 0; } void matMult(int A[][5], int B[][5], int C[][5]) { int i; int j; int k; for(i = 0; i <= 2; i++) { for(j = 0; j <= 4; j++) { for(k = 0; k <= 3; k++) { C[i][j] += A[i][k] * B[k][j]; } } } } int printMat_5x5(int A[5][5]){ int i; int j; for (i = 0;i < 5;i++) { for(j = 0;j < 5;j++) { printf("%2d",A[i][j]); } printf("\n"); } } EDIT: Here is the question, sorry for not posting it the first time. (2) Write a C function to multiply two five by five matrices. The prototype should read void matMult(int a[][5],int b[][5],int c[][5]); The resulting matrix product (a times b) is returned in the two dimensional array c (the third parameter of the function). Program your solution using three nested for loops (each generating the counter values 0, 1, 2, 3, 4) That is, DO NOT code specific formulas for the 5 by 5 case in the problem, but make your code general so it can be easily changed to compute the product of larger square matrices. Write a main program to test your function using the arrays a: 1 2 3 4 6 6 1 5 3 8 2 6 4 9 9 1 3 8 3 4 5 7 8 2 5 b: 3 5 0 8 7 2 2 4 8 3 0 2 5 1 2 1 4 0 5 1 3 4 8 2 3 Print your matrices in a neat format using a C function created for printing five by five matrices. Print all three matrices. Generate your test arrays in your main program using the C array initialization feature. enter code here

    Read the article

  • polynomial multiplication using fastfourier transform

    - by mawia
    i am going through the above topic from CLRS(CORMEN) (page 834) and I got stuck at this point. Can anybody please explain how the following expression, A(x)=A^{[0]}(x^2) +xA^{[1]}(x^2) follows from, n-1 ` S a_j x^j j=0 Where, A^{[0]} = a_0 + a_2x + a_4a^x ... a_{n-2}x^{\frac{n}{2-1}} A^{[1]} = a_1 + a_3x + a_5a^x ... a_{n-1}x^{\frac{n}{2-1}} WITH REGARDS THANKS

    Read the article

  • Small-o(n^2) implementation of Polynomial Multiplication

    - by AlanTuring
    I'm having a little trouble with this problem that is listed at the back of my book, i'm currently in the middle of test prep but i can't seem to locate anything regarding this in the book. Anyone got an idea? A real polynomial of degree n is a function of the form f(x)=a(n)x^n+?+a1x+a0, where an,…,a1,a0 are real numbers. In computational situations, such a polynomial is represented by a sequence of its coefficients (a0,a1,…,an). Assuming that any two real numbers can be added/multiplied in O(1) time, design an o(n^2)-time algorithm to compute, given two real polynomials f(x) and g(x) both of degree n, the product h(x)=f(x)g(x). Your algorithm should **not** be based on the Fast Fourier Transform (FFT) technique. Please note it needs to be small-o(n^2), which means it complexity must be sub-quadratic. The obvious solution that i have been finding is indeed the FFT, but of course i can't use that. There is another method that i have found called convolution, where if you take polynomial A to be a signal and polynomial B to be a filter. A passed through B yields a shifted signal that has been "smoothed" by A and the resultant is A*B. This is supposed to work in O(n log n) time. Of course i am completely unsure of implementation. If anyone has any ideas of how to achieve a small-o(n^2) implementation please do share, thanks.

    Read the article

  • Using pthread to perform matrix multiplication

    - by shadyabhi
    I have both matrices containing only ones and each array has 500 rows and columns. So, the resulting matrix should be a matrix of all elements having value 500. But, I am getting res_mat[0][0]=5000. Even other elements are also 5000. Why? #include<stdio.h> #include<pthread.h> #include<unistd.h> #include<stdlib.h> #define ROWS 500 #define COLUMNS 500 #define N_THREADS 10 int mat1[ROWS][COLUMNS],mat2[ROWS][COLUMNS],res_mat[ROWS][COLUMNS]; void *mult_thread(void *t) { /*This function calculates 50 ROWS of the matrix*/ int starting_row; starting_row = *((int *)t); starting_row = 50 * starting_row; int i,j,k; for (i = starting_row;i<starting_row+50;i++) for (j=0;j<COLUMNS;j++) for (k=0;k<ROWS;k++) res_mat[i][j] += (mat1[i][k] * mat2[k][j]); return; } void fill_matrix(int mat[ROWS][COLUMNS]) { int i,j; for(i=0;i<ROWS;i++) for(j=0;j<COLUMNS;j++) mat[i][j] = 1; } int main() { int n_threads = 10; //10 threads created bcos we have 500 rows and one thread calculates 50 rows int j=0; pthread_t p[n_threads]; fill_matrix(mat1); fill_matrix(mat2); for (j=0;j<10;j++) pthread_create(&p[j],NULL,mult_thread,&j); for (j=0;j<10;j++) pthread_join(p[j],NULL); printf("%d\n",res_mat[0][0]); return 0; }

    Read the article

  • Multiplication of 2 positive numbers giving a negative result

    - by krandiash
    My program is an implementation of a bloom filter. However, when I'm storing my hash function results in the bit array, the function (of the form f(i) = (a*i + b) % m where a,b,i,m are all positive integers) is giving me a negative result. The problem seems to be in the calculation of a*i which is coming out to be negative. Ignore the print statements in the code; those were for debugging. Basically, the value of temp in this block of code is coming out to be negative and so I'm getting an ArrayOutOfBoundsException. m is the bit array length, z is the number of hash functions being used, S is the set of values which are members of this bloom filter and H stores the values of a and b for the hash functions f1, f2, ..., fz. public static int[] makeBitArray(int m, int z, ArrayList<Integer> S, int[] H) { int[] C = new int[m]; for (int i = 0; i < z; i++) { for (int q = 0; q < S.size() ; q++) { System.out.println(H[2*i]); int temp = S.get(q)*(H[2*i]); System.out.println(temp); System.out.println(S.get(q)); System.out.println(H[2*i + 1]); System.out.println(m); int t = ((H[2*i]*S.get(q)) + H[2*i + 1])%m; System.out.println(t); C[t] = 1; } } return C; } Any help is appreciated.

    Read the article

  • Help with Assembly/SSE Multiplication

    - by Brett
    I've been trying to figure out how to gain some improvement in my code at a very crucial couple lines: float x = a*b; float y = c*d; float z = e*f; float w = g*h; all a, b, c... are floats. I decided to look into using SSE, but can't seem to find any improvement, in fact it turns out to be twice as slow. My SSE code is: Vector4 abcd, efgh, result; abcd = [float a, float b, float c, float d]; efgh = [float e, float f, float g, float h]; _asm { movups xmm1, abcd movups xmm2, efgh mulps xmm1, xmm2 movups result, xmm1 } I also attempted using standard inline assembly, but it doesn't appear that I can pack the register with the four floating points like I can with SSE. Any comments, or help would be greatly appreciated, I mainly need to understand why my calculations using SSE are slower than the serial C++ code? I'm compiling in Visual Studio 2005, on a Windows XP, using a Pentium 4 with HT if that provides any additional information to assit. Thanks in advance!

    Read the article

  • question about polynomial multiplication

    - by davit-datuashvili
    i know that horners method for polynomial pultiplication is faster but here i dont know what is happening here is code public class horner{ public static final int n=10; public static final int x=7; public static void main(String[] args){ //non fast version int a[]=new int[]{1,2,3,4,5,6,7,8,9,10}; int xi=1; int y=a[0]; for (int i=1;i<n;i++){ xi=x*xi; y=y+a[i]*xi; } System.out.println(y); //fast method int y1=a[n-1]; for (int i=n-2;i>=0;i--){ y1=x*y+a[i]; } System.out.println(y1); } } result of this two methods are not same result of first method is 462945547 and result of second method is -1054348465 please help

    Read the article

  • List multiplication

    - by Schitti
    Hi, Python newbie here. I have a list L = [a, b, c] and I want to generate a list of tuples : [(a,a), (a,b), (a,c), (b,a), (b,b), (b,c)...] I tried doing L * L but it didn't work. Can someone tell me how to get this in python.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11  | Next Page >