From 8f0461690d9a885ffae5e0a7117aff460ab27ab7 Mon Sep 17 00:00:00 2001
From: LakshmiKalaKadali <149650845+LakshmiKalaKadali@users.noreply.github.com>
Date: Tue, 7 Jan 2025 00:34:44 +0530
Subject: [PATCH] Specify window_length dtype requirement in tf.keras.ops.istft
 in math.py (#20728)

The `window_length` parameter in `tf.keras.ops.istft` requires `tf.int32` dtype, but this isn't documented. This can cause unexpected `ValueError` when using `tf.int64` and `tf.int16`

Here is the Example case:
```
import tensorflow as tf

input_dict = {
    'stfts': tf.constant([[-0.87817144+1.14583987j, -0.32066484+0.25565411j]], dtype=tf.complex128),
    'frame_length': tf.constant(256, dtype=tf.int16),
    'frame_step': tf.constant(5120,dtype=tf.int64)
}
result = tf.signal.inverse_stft(**input_dict)
print(result)
```
The code throws the following error:
```
ValueError: window_length: Tensor conversion requested dtype int32 for Tensor with dtype int64
```
---
 keras/src/ops/math.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/keras/src/ops/math.py b/keras/src/ops/math.py
index 7caaa41f6283..6cedef62cee4 100644
--- a/keras/src/ops/math.py
+++ b/keras/src/ops/math.py
@@ -888,7 +888,7 @@ def istft(
         sequence_length: An integer representing the sequence length.
         sequence_stride: An integer representing the sequence hop size.
         fft_length: An integer representing the size of the FFT that produced
-            `stft`.
+            `stft`. Should be of type `int32`.
         length: An integer representing the output is clipped to exactly length.
             If not specified, no padding or clipping take place. Defaults to
             `None`.