Linked Questions

50
votes
3answers
2k views

Are there guidelines for avoiding the unpacking of a packed array?

Packed arrays are very useful because they save memory and generally allow speedier and more efficient calculation times. If a list of data currently stored as a packed array is unpacked, it can slow ...
110
votes
1answer
2k views

Why are numeric division and subtraction not handled better in Mathematica?

There is something that has been troubling me for a while. At least through version 10.0 the performance of a / b and a - b is ...
12
votes
4answers
2k views

Grid - sizing and spacing problems with spanning cells

I am trying to set up a Grid with cells that span two rows and are centered on those rows, but I am having troubles with the sizing and, therefore, spacing of the ...
11
votes
3answers
947 views

Distorted graphics when using custom ticks and AspectRatio -> Full

Bug introduced in 7.0.1 or earlier and persists through 12.0 I am having a problem using custom tick specifications along with AspectRatio -> Full. The problem ...
4
votes
3answers
289 views

Efficiently test membership for a list of values

I have two lists: excluded and values. I would like to efficiently determine whether excluded...
17
votes
4answers
701 views

Grid - Item - Alignment to decimal problem

Bug introduced in 7.0 or earlier and persisting through 12.0 or later I've run into a Grid layout problem for which I don't know a solution. I want to specify ...
12
votes
2answers
557 views

Grid - problem with ItemSize being ignored

Bug introduced in 7.0 or earlier and persisting through 11.0 I have run into another problem with Grid today. An explicitly specified ...
5
votes
2answers
269 views

Improving performance in the generation of random (directed acyclic) graphs

I need to generate large (directed, acyclic, transitive) graphs. My code in Mathematica gets very slow for large numbers of vertices. I've tried a number of approaches and I can't find any significant ...
7
votes
3answers
405 views

Appending and Prepending columns to a dataset in 10.0.2.0

fixed in 10.1 (windows) I just experience a problem in prepending columns to a dataset. I did this a hundred times in 10.0.1.0 - no problems. Now it seems as if it is only possible to append/prepend ...
1
vote
1answer
450 views

Averaging multiple 2D data sets

I have multiple data sets, each of which is a 2D matrix. I want to construct a new 2D Matrix in which each element is the average of that element for all the original data sets. i.e ...