# Segmentation fault
**URL:** https://forum.opencv.org/t/segmentation-fault/1260
**Category:** Uncategorized
**Tags:** ml
**Created:** [February 1, 2021, 5:36pm UTC](https://forum.opencv.org/t/segmentation-fault/1260 "2021-02-01T17:36:23Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Jan\_Hackenberg](https://forum.opencv.org/u/Jan_Hackenberg)
#### Post date: [February 1, 2021, 5:36pm UTC](https://forum.opencv.org/t/segmentation-fault/1260/1 "2021-02-01T17:36:24Z")
I am trying to execute based on [example code](https://programming.vip/docs/gmm-gaussian-mixture-model-method-for-opencv-image-segmentation.html):
```
using namespace cv;
using namespace cv::ml;
// mat is a Mat containing the features computed beforehand
Ptr model = EM::create();
model->setClustersNumber(static_cast(m_numberClusters));
Mat logs, labels, probs;
model->trainEM(mat, logs, labels, probs);
```
**setClustersNumber** gives a segmentation fault, if commented out then **trainEM** does. Debugging reveals, that those are pure virtual functions, which is in coincidence with [OpenCV API](https://docs.opencv.org/3.4/d1/dfb/classcv_1_1ml_1_1EM.html).
See here:
[](https://i.stack.imgur.com/BZt8V.png)
Nevertheless I do not find any implementation class having those pure virtual functions nor other examples for Expectation Maximization by OpenCV with 3.x.x versions.
[](https://i.stack.imgur.com/j2zZx.png)
[](https://i.stack.imgur.com/g2HZd.png)
---
### Author:  [@crackwitz](https://forum.opencv.org/u/crackwitz)
#### Post date: [February 1, 2021, 9:11pm UTC](https://forum.opencv.org/t/segmentation-fault/1260/2 "2021-02-01T21:11:08Z")
related:
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