From a8abd18483cd113d1b0ee066621caf83bafe87f8 Mon Sep 17 00:00:00 2001
From: Connor Moore <connor@hhmoore.ca>
Date: Wed, 4 Feb 2026 17:47:21 -0500
Subject: Added more comments in Makefile

---
 Makefile | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Makefile b/Makefile
index d822d45..261eb4a 100644
--- a/Makefile
+++ b/Makefile
@@ -8,17 +8,23 @@ OPTFLAGS ?= O3
 # For the parallel runs, use all available processors
 NPROC := $(shell nproc)
 
+# Make some pretty colours
 MAGENTA  := \033[1;35m
 RESET  := \033[0m
 
+# Define the start, stop, and step for "short" runs (including triple loops)
 S_START:= 100
 S_END  := 300
 S_STEP := 100
 
+# And the step and end for "long" runs without triple loops.
+# Automatically they start at S_END defined earlier
 L_END  := 800
 L_STEP := 500
 
+
 all:
+	# This target simply compiles the binaries
 	@mkdir -p bin/
 	@echo "$(MAGENTA)Compiling serial and parallel binaries with $(OPTFLAGS)$(RESET)"
 	$(GCC) matrixproduct.f90 -o bin/$(GCC).serial.out -$(OPTFLAGS) -fexternal-blas -lopenblas -march=native
@@ -27,6 +33,7 @@ all:
 	$(oneAPI) matrixproduct.f90 -o bin/$(oneAPI).parallel.out -qmkl=parallel -$(OPTFLAGS) -heap-arrays -xHost -fopenmp
 
 tests: clean
+	# Run the parametric tests and sweep over compiler flags
 	@mkdir -p results/
 	@for opt in $(FLAGS); do \
                 $(MAKE) all OPTFLAGS=$$opt; \
@@ -36,7 +43,14 @@ tests: clean
 				$(MAKE) parallel OPTFLAGS=$$opt; \
 	done
 
+
+## NOTE: For the below two, it is very important that lines have the '\' postfix
+## By default, these are all executed on a different shell session, so to preserve
+## the enivronment variables for OMP/MKL they need to be run as one "big" command
+## serially. The backslash is the 'line continuation' operator that does this.
+
 serial: ./bin/gfortran.serial.out ./bin/ifx.serial.out
+	# run the serial tests. ensures that only one thread is used for blas and mkl
 	export OMP_NUM_THREADS=1 && \
 	export MKL_NUM_THREADS=1 && \
 	./bin/$(GCC).serial.out $(S_START) $(S_END) $(S_STEP) yes | tee results/$(GCC)_short_serial_$(OPTFLAGS).out; \
@@ -45,6 +59,8 @@ serial: ./bin/gfortran.serial.out ./bin/ifx.serial.out
 	./bin/$(oneAPI).serial.out $(S_END) $(L_END) $(L_STEP) no | tee results/$(oneAPI)_long_serial_$(OPTFLAGS).out; 
 
 parallel: ./bin/gfortran.parallel.out ./bin/ifx.parallel.out	
+	# run the parallel tests. ensures that all threads are used for the loops, blas, and mkl
+	export OMP_NUM_THREADS=1 && \
 	export OMP_NUM_THREADS=${NPROC} && \
 	export MKL_NUM_THREADS=${NPROC} && \
 	./bin/$(GCC).parallel.out $(S_START) $(S_END) $(S_STEP) yes | tee results/$(GCC)_short_parallel_$(OPTFLAGS)_$(NPROC).out; \
@@ -54,9 +70,11 @@ parallel: ./bin/gfortran.parallel.out ./bin/ifx.parallel.out
 
 
 plots:
+	# Deprecated. Plot some things in GNUPLOT. Currently unused.
 	gnuplot -p plots.gnu
 
 clean:
+	# Clean up after ourselves
 	@echo "$(MAGENTA)Cleaning bin/ and results/$(RESET)"
 	@rm -rf bin/
 	@rm -rf results/
-- 
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