From 0ef0eeb0479e28b41883078732447be813a97da3 Mon Sep 17 00:00:00 2001
From: Elias Kohout <elias@kohout.de>
Date: Sat, 18 Mar 2023 20:56:40 +0100
Subject: [PATCH] Added tensor subtraction.

---
 tensor.c | 16 ++++++++++++++++
 tensor.h |  1 +
 2 files changed, 17 insertions(+)

diff --git a/tensor.c b/tensor.c
index 234b70b..4477d4b 100644
--- a/tensor.c
+++ b/tensor.c
@@ -238,6 +238,22 @@ int tensor_add(tensor t1, const tensor t2)
 	return 1;
 }
 
+int tensor_sub(tensor t1, const tensor t2)
+{
+	assert(!tensor_is_empty(t1));
+	assert(!tensor_is_empty(t2));
+
+	int i;
+	if(t1->dimension != t2->dimension) return 0;
+	for(i = 0; i < t1->dimension; i++) {
+		if(t1->size[i] != t2->size[i]) return 0;
+	}
+	for(i = 0; i < t1->num_elem; i++) {
+		t1->elements[i] -= t2->elements[i];
+	}
+	return 1;
+}
+
 void tensor_for_each_elem(tensor t, dtype (*func)(dtype))
 {
 	assert(!tensor_is_empty(t));
diff --git a/tensor.h b/tensor.h
index c53e7e1..bf29307 100644
--- a/tensor.h
+++ b/tensor.h
@@ -42,6 +42,7 @@ void tensor_sub_scalar(tensor t, dtype n);
 void tensor_mult_scalar(tensor t, dtype n);
 void tensor_div_scalar(tensor t, dtype n);
 int tensor_add(tensor t1, const tensor t2);
+int tensor_sub(tensor t1, const tensor t2);
 
 void tensor_for_each_elem(tensor t, dtype (*func)(dtype));
 void tensor_print(const tensor t);