multiplication

I have two tensor: x is 2-by-2-by-3, y is also 2-by-2-by-3. Define each frontal slice of tensor is x1 x2 x3,y1,y2,y3. xi or yi are 2-by-2 matrix. How can I do kronecker product between x and y in matlab? What I want to get is kron(x1,y1),kron(x2,y2),kron(x3,y3) in matlab simultaneously without any looping. This could be one approach - %// Pre-processing part [m,n,r] = size(x) %// Get size N = m*n %// number of elements in one 3D slice %// ------------- PART 1: Get indices for each 3D slice %// Get the first mxm block of kron-corresponding indices and then add to %// each such block for the

I want to implement multiplication of two integer numbers without using multiplication operator, in .NET public uint MultiplyNumbers(uint x, uint y) { } Any idea! I'm assuming this is homework... otherwise there's no sane reason you'd want to do it. Therefore I'll just give hints... If performance isn't terribly important, consider that x * 3 = x + x + x ... think about using a loop. If performance is important but you know that one of the numbers will be small, loop on the smaller number. If performance is important and both numbers could be large, you'll need to think about bit-twiddling.

Consider the following as a reference implementation: /* calculates (a * b) / c */ uint32_t muldiv(uint32_t a, uint32_t b, uint32_t c) { uint64_t x = a; x = x * b; x = x / c; return x; } I am interested in an implementation (in C or pseudocode) that does not require a 64-bit integer type. I started sketching an implementation that outlines like this: /* calculates (a * b) / c */ uint32_t muldiv(uint32_t a, uint32_t b, uint32_t c) { uint32_t d1, d2, d1d2; d1 = (1 << 10); d2 = (1 << 10); d1d2 = (1 << 20); /* d1 * d2 */ return ((a / d1) * (b /d2)) / (c / d1d2); } But the difficulty is to pick

In fixed point math I use a lot of 16bit signals and perform multiplication with 32bit intermediate results. For example: int16_t a = 16384; //-1.0q14 or 1.0*2^14 int16_t b = -24576; // -1.4q14 or 1.4*2^14 int16_t c; // result will be q14 c = (int16_t)(((int32_t)a * (int32_t)b)>>14); Lets say a is a q14 number then c with have the same scaling as b. This is fine and works for unsigned as well as signed arithmetic. The question is: What happens if I were to mix types? For example if I know the multiplier "a" is always going to range from 0.0 to 1.0, it is tempting to make it an unsigned int q15

I'm probably being incredibly stupid here but I'm having trouble doing some basicaly Mat multiplication using OpenCV for Android. I have two Mat's both of the same type, CV_64F mat1 has size: 3 rows, 3 cols mat2 has size: 3 rows, 1 cols I want to multiply them to give the product mat3 of size 3 rows, 1 cols. I've tried using: Mat mat3 = new Mat(3, 1, CvType.CV_64F); Core.multiply(mat1, mat2, mat3); But I get an error: CvException [org.opencv.core.CvException:/home/andreyk/OpenCV2/trunk/opencv_2.3.1.b2/modules/core/src/arithm.cpp:1253: error: (-209) The operation is neither 'array op array'

For performance reasons, I'm curious if there is a way to multiply a stack of a stack of matrices . I have a 4-D array (500, 201, 2, 2). Its basically a 500 length stack of (201,2,2) matrices where for each of the 500, I want to multiply the adjacent matrices using einsum and get another (201,2,2) matrix. I am only doing matrix multiplication on the [2x2] matrices at the end. Since my explanation is already heading off the rails, I'll just show what I'm doing now, and also the 'reduce' equivalent and why its not helpful (because its the same speed computationally). Preferably this would be a