--- ray/doc/man/man1/rcomb.1	2024/05/07 17:15:31	1.7
+++ ray/doc/man/man1/rcomb.1	2024/05/22 16:49:19	1.9
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: rcomb.1,v 1.7 2024/05/07 17:15:31 greg Exp $"
+.\" RCSid "$Id: rcomb.1,v 1.9 2024/05/22 16:49:19 greg Exp $"
 .TH RCOMB 12/5/2023 RADIANCE
 .SH NAME
 rcomb - combine and convert matrices a row at a time
@@ -11,6 +11,8 @@ rcomb - combine and convert matrices a row at a time
 ][
 .B \-f[afdc]
 ][
+.B "\-n nproc"
+][
 .B "\-f file"
 ][
 .B "\-e expr"
@@ -141,12 +143,11 @@ or
 is specified for an input picture or the
 .I "-fc"
 option is given, the output will be written as a RGBE or XYZE picture.
-Note that conversion from a float or RGBE color space applies a conversion
+Note that conversion from a float or RGBE color space applies an efficacy factor
 of 179 lumens/watt (for CIE or melanopic output) or 412 (for scotopic output),
-and the reverse happens for conversion from XYZE input to RGB or RGBE output.
+and the inverse happens for conversion from XYZE input to RGB or RGBE output.
 Lower case versions of all these components are also supported, the only
-difference is that the aforementioned efficacy factors
-will be left out of the conversion.
+difference being that the efficacy factors are ignored.
 .PP
 If a matrix or picture file path is given to the
 .I \-c
@@ -250,6 +251,13 @@ The
 .I \-w
 option turns off warnings about divide-by-zero and other non-fatal
 calculation errors.
+.PP
+The
+.I \-n
+option specifies how many execution processes to employ,
+which may improve performance on multi-core architectures,
+especially for matrix multiplication
+and complex operations on long input rows.
 .SH EXAMPLES
 To convert two hyperspectral inputs to RGB color space,
 average them together, and write them out as a RADIANCE picture: