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--- internal:administration:idl [2026/03/31 16:22] – [matrix multiplication] jan
+++ internal:administration:idl [2026/07/18 07:57] (current) – [type setting] jan
@@ Line 609: / Line 609: @@
   * One can use this to generate matrices with a variable increasing only in one dimension and arrays of function values:
-  * Alternatively one may use rebin
-  x = fltarr(Nx)
-  y = fltarr(Ny)
-  xx = rebin( x, Nx, Ny )
-  yy = rebin( y, Ny, Nx )
   ; generate Nx*Ny Matrix xx with Nx values increasing in x-direction from xa to xb
@@ Line 631: / Line 626: @@
   * As matrix operations are faster than for-loops this may speed up your code a lot ...
+  * Alternatively one may use **rebin** , but note that rebin uses bilinear interpolation (sample=0) or nearest neigbor (sample=1) and accordingly might be a bit slower
+  x = fltarr(Nx)
+  y = fltarr(Ny)
+  xx = rebin( x, Nx, Ny, sample=1 )
+  yy = transpose(rebin( y, Ny, Nx ))
 ==== procedure names ====
@@ Line 2195: / Line 2198: @@
 The following commands are available (see also IDL help [[https://www.nv5geospatialsoftware.com/docs/Embedded_Formatting_Comm.html|Embedded Formatting Commands]])((find it under 'fonts' in the help)):
-  * supersuperscript  !U ('Up' faktor 0.62)
+  * superscript  !U ('Up' faktor 0.62 or -38%)
-  * subscript    !D ('Down' faktor 0.62)
+  * subscript    !D ('Down' faktor 0.62 or -38%)
-  * subsubscript !L ('Low' faktor 0.62)
+  * subsubscript !L ('Low' faktor 0.62 or -38%)
-  * index        !I (faktor 0.44)
+  * index        !I (faktor 0.44 or -56%)
-  * exponent     !E (faktor 0.44)
+  * exponent     !E (faktor 0.44 or -56%)
   * back to Normal !N
-  * numerator position !A ('above' division line)
+  * numerator !A ('above' division line)
-  * denominator position !B ('below' division line)
+  * denominator !B ('below' division line)
   * new line !C ('carriage return')
   * special characters !Z(b1[,b2[,...]]) where b1,b2,... are the 16 bit hexadecimal unicode codes of the desired character[s]
@@ Line 2209: / Line 2212: @@
   * exclamation mark !!
-Most of these commands only affect the vertical position except for %%!R%% which restrores also the horizontal position.
+Most of these commands only affect the vertical position except for %%!R%% which restores also the horizontal position.
+The exponent (%%!E%%) and index (%%!I%%) charactersizes are really tiny, better use the %%!U%% and %%!D%%.
+To test you may use
+  xyouts, 100,100, 'look!S!Uup!N!R!Ddown!N!Llow!N do!S!Iidx!N!R!Eexp!N !S!Anumerator!R!Bdemnominator!N', /device, charsize=1
 Examples:
@@ Line 3848: / Line 3856: @@
 If you want to interpolate only over certain dimensions they must be the last ones. You may use transpose to rearrange. Lets assume you have an array depending on x, y and time, i.e. z=fltarr(Nx,Ny,Nt) and you want to interpolate to certain x and y coordinates you can do this as follows:
-  z_ipol = transpose( interpolate( transpose(z_org,[2,0,1]) , ix_ipol , iy_ipol , /grid  ), [1,2,0] )
+  z_ipol = transpose( interpolate( transpose(z_org,[2,0,1]) , ix_ipol , iy_ipol , /grid, MISSING=!VALUES.f_nan  ), [1,2,0] )
+The /GRID flag allow to use different sizes for ix_ipol and iy_ipol and the MISSING keyword sets values of z_ipol outside the ranges of z_org to the missing value (no extrapolation).