[MINC-users] mincmath

[Mishkin Derakhshan]

Hi Jerome,
If you haven't discovered it by now, the minccalc -expression command is
also great for both simple and advanced calculations.

Here is an example of subtraction
mincmath -expression "A[0]-A[1]" a.mnc B.mnc out.mnc
A[0] is the first mmc file specified on the command line, so a.mnc
A[1] is the second input, so B.mnc
and out.mc is the output file where the result of a.mnc-B.mnc would go. If
you wanted B.mnc - a.mnc, you could either change the expression to read
"A[1]-A[0]" or you could leave the expression as is, and just change the
ordering of your input files:
mincmath -expression "A[0]-A[1]" B.mnc a.mnc out.mnc

There are lots of other types of expressions possible, but one of the most
useful ones I've used is the if/else
mincmath -expr "A[1] != 0 ? A[0]/A[1]:0" a.mnc b.mnc out.mnc

The general syntax of the expression is first evaluate the stuff before the
?, if it is true, then in the output file you put the stuff on the left of
the colon, else, write out the stuff on the right of the :

So the above would read, if a voxel in A[1] is not equal to zero, then in
the output file put in A[0] divided by A[1]. And if A[1] is equal to zero,
then instead of outputting the division, just output 0. Like in the above
a.mnc maps to A[0] and b.mnc maps to A[1].

See the minccalc man page for lots of documentation.

hth,
mishkin


On Tue, Sep 22, 2015 at 4:56 AM, Andrew Janke <a.janke at gmail.com> wrote:

> Hi Jerome,
>
> The first is correct (this one):
>
>    mincmath -sub A.mnc B.mnc out.mnc
>
>
> Be careful of div zero effects when using divide and mincmath.
>
>
> a
>
>
> On 23 September 2015 at 00:50, Jérôme Redouté <redoute at cermep.fr> wrote:
> > Hi All,
> > just a naive question concerning mincmath syntax:
> >
> > if you want to substract 2 volumes : A - B
> >
> > the correct syntax is:
> >
> > mincmath -sub A.mnc B.mnc out.mnc
> >
> > or
> >
> > mincmath -sub B.mnc A.mnc out.mnc
> >
> > (same question for -div  ;)
> >
> > Thank you
> > JR
> >
> > --
> > ==================================================================
> > Jérôme Redouté
> > Ph.D. - Ingénieur de Recherche - Université Claude Bernard - Lyon1
> > CERMEP - Imagerie du vivant
> > 59 Bd Pinel. 69677 Bron - FRANCE
> > tel : 33 (0)4 72 68 86 18 (bureau)
> > tel : 33 (0)4 72 68 86 00 (standard)
> > fax : 33 (0)4 72 68 86 10
> > ==================================================================
> >
> >
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