format +

[John W. Eaton]

On 28-Jun-1999, address@hidden <address@hidden> wrote:

| In Octave, "format +" is described thus:
| 
|     `+'
|           Print a `+' symbol for nonzero matrix elements and a space
|           for zero matrix elements.  This format can be very useful for
|           examining the structure of a large matrix.
| 
| In Matlab 3.5, it is described thus:
| 
|           FORMAT +       Compact format. The symbols +, - and blank
|                          are printed for positive, negative and zero
|                          elements. Imaginary parts are ignored.  
| 
| The Octave effect can easily be mimicked from Matlab, i.e.
|   format +; abs(A)
| but the effect of the Matlab code
|   format +; A
| requires manual creation and population of a character matrix in Octave.
| 
| Is this not a case where Matlab compatiblity would be a good thing?

I think it is bad design to ignore imaginary parts without at least a
warning.

How about using

  +      positive real
  -      negative real
  c      complex
  i      pure imaginary
  blank  zero

instead?  I can also imagine that people might want to select their
own characters to display for arbitrary conditions, but that is
probably best left to a specialized function.

jwe



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