## 121 Reputation

18 years, 87 days

## MaplePrimes Activity

### These are questions asked by jimmyinhmb

Hello, Maple wizards.

Can we talk about how to perform arithmetic efficiently on submatrices? To illustrate, let matrices A and B be represented by a block structure using submatrices, so that A and B are

A11  A12
A21  A22

and

B11 B12
B21 B22

respectively. I want to efficiently replace the lower submatrix A21 A22  with A21+B21   A22+B22.

Here's the catch (to me, anyway): the indices representing...

## How do I efficiently share and multiply ...

Maple 15

Hello Maple wizards,

I have two questions for you today.

First, a program I'm developing in Maple 15 does frequent matrix multiplication with a constant float[8] matrix. I hope to take advantage of multiple processors in my 6-way desktop processor and/or CUDA features of the Nvidia GPU card. The program is large enough that maintainability and good programming practice dictate that it be broken down into multiple procs. In addition, I'm considering...

## Reducing FP round off and catastrophic c...

Maple 14

Hello Maple wizards,

I am working with thousands of fairly large (at least 11K nonzero entries) strictly lower triangular Arrays containing positive and negative floating point numbers, including float(1,infinity). The Arrays are the same size and each one can be processed independently, so I hope to avoid a space explosion by having each Array overwrite the previous one -- lhs(entry) and all that. I do see a steady leakage not recovered by gc, but that's not tonight's question.

Maple 14

Hello wizards,

I'm given to understand that using add() or if possible Task:-Add() is more efficient than a FOR...DO loop. Today I'm asking about the limits of this generalization. My illustration is probably missing some evalf's, but hopefully the concept is clear:

A computation I'm working on involves between 10E4 and 10E6 computations like

## Array or list for sharing large immutabl...

Maple 14

I'm using Maple 14 on 4-way and 6-way AMD 64 hardware running Windows Vista to numerically estimate inverses of a cumulative distribution function at hundreds of points, and am using the Task model to assign each point's inverse computation to a separate task. The cdf is a weighted sum of thousands of simpler functions, and so each task needs the weights. Initially I had set these up as a global variable, but after reading Darin Ohashi's MaplePrime's post ...

 1 2 3 Page 1 of 3
﻿