--- ray/doc/man/man1/rcomb.1	2024/05/22 16:49:19	1.9
+++ ray/doc/man/man1/rcomb.1	2025/06/19 22:36:53	1.14
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: rcomb.1,v 1.9 2024/05/22 16:49:19 greg Exp $"
+.\" RCSid "$Id: rcomb.1,v 1.14 2025/06/19 22:36:53 greg Exp $"
 .TH RCOMB 12/5/2023 RADIANCE
 .SH NAME
 rcomb - combine and convert matrices a row at a time
@@ -25,7 +25,7 @@ rcomb - combine and convert matrices a row at a time
 ]
 .B "m1 .."
 [
-.B "\-m mcat"
+.B "\-m[t] mcat"
 ]
 .SH DESCRIPTION
 .I Rcomb
@@ -60,6 +60,9 @@ A single concatenation matrix may be applied after ele
 using the
 .I \-m
 option.
+If the option is given as
+.I \-mt
+then the concatenation matrix will be transposed before it is applied.
 Matrix concatenation will happen before or after any trailing
 operations, depending on relative command line placement.
 .PP
@@ -259,10 +262,10 @@ which may improve performance on multi-core architectu
 especially for matrix multiplication
 and complex operations on long input rows.
 .SH EXAMPLES
-To convert two hyperspectral inputs to RGB color space,
+To convert two hyperspectral pictures to RGB color space,
 average them together, and write them out as a RADIANCE picture:
 .IP "" .2i
-rcomb -C RGB -s .5 img1.spc -s .5 img2.spc > avg.hdr
+rcomb -C RGB -s .5 img1.hsr -s .5 -fc img2.hsr > avg.hdr
 .PP
 Divide one set of matrix elements by the Euclidean sum of two others:
 .IP "" .2i
@@ -272,9 +275,9 @@ inp2.mtx inp3.mtx > out.mtx
 Compute the absolute and relative differences between melanopic and photopic values
 in a spectral image:
 .IP "" .2i
-rcomb -fa -C MY -e "abs(x):if(x,x,-x)"
+rcomb -C MY -e "abs(x):if(x,x,-x)"
 -e "co(p)=select(p,abs(ci(1,1)-ci(1,2)),(ci(1,1)-ci(1,2))/ci(1,2))"
-input_spec.hsr > compare.mtx
+input_spec.hsr -fa > compare.mtx
 .PP
 Concatenate a spectral flux coefficient matrix with a spectral sky
 matrix to compute a set of melanopic lux values:
@@ -339,6 +342,14 @@ is not supported in
 .I rcomb,
 and should instead be handled by
 .I pfilt(1).
+.PP
+Similar to
+.I rmtxop,
+all calculations are peformed internally using 32-bit floating-point,
+so there is little benefit in either reading or writing 64-bit double
+data.
+This may be overridden at compile time using the macro
+"-DDTrmx_native=DTdouble".
 .SH BUGS
 The
 .I rcomb
@@ -349,6 +360,6 @@ circumstances where it would make sense to.
 Greg Ward
 .SH "SEE ALSO"
 dctimestep(1), icalc(1), getinfo(1), pcomb(1), pfilt(1),
-ra_xyze(1), rcalc(1),
+pvsum(1), ra_rgbe(1), ra_xyze(1), rcalc(1),
 rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), 
 rmtxop(1), rtpict(1), rtrace(1), vwrays(1)