# Numpy question **URL:** \ **Category:** GNU Radio\ **Created:** [July 6, 2015, 5:55pm UTC](https://www.ruby-forum.com/t/numpy-question/242603 "2015-07-06T17:55:18Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [July 6, 2015, 5:55pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/1 "2015-07-06T17:55:18Z")
I’m trying to build gnuradio for a system without numpy. cmake reports correctly ## – – Python checking for pygtk \>= 2.10.0 – Python checking for pygtk \>= 2.10.0 - not found ## – Python checking for numpy – Python checking for numpy - not found – Configuring gnuradio-companion support… make reports Linking CXX shared library libgnuradio-pmt-3.7.8git.so and the library exists in the install directory. But running an example leads to pmt\_to\_python.py", line 22, in ImportError: No module named numpy How can I come around this problem without installing numpy ? – Volker ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 6:30pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/2 "2015-07-06T18:30:57Z")
On 06.07.2015 08:54, Volker S. wrote: > I’m trying to build gnuradio for a system without numpy. Numpy should probably be a hard requirement – Python blocks won’t work properly without it, even disregarding this specific module. > How can I come around this problem without installing numpy ? Unless you want to disable Python support entirely, you can’t. Cheers, Martin ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 9:44pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/3 "2015-07-06T21:44:22Z")
That means,there is a bug in cmake. If numpy is required , then gnuradio should not build if numpy is not found. But if I remember well, in earlier days of gnuradio pmt was not required. – Volker Am 06.07.2015 um 18:27 schrieb Martin B.: ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 10:04pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/4 "2015-07-06T22:04:49Z")
A quick look at the source reveals NumPy is used extensively in GNU Radio, but it is checked for by the gr-wxgui and grc modules only. So, most of GNU Radio can install properly even if NumPy is not installed or working. - MLD ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 10:09pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/5 "2015-07-06T22:09:30Z")
That’s right, but the problem is pmt. Is it really required for gnuradio to run ? Am 06.07.2015 um 22:03 schrieb Michael D.: ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 10:17pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/6 "2015-07-06T22:17:06Z")
To be more specific: Is pmt\_to\_python.py required as that’s the place wher numpy is called. But if this is required gnuradio should not compile without numpy. Am 06.07.2015 um 22:09 schrieb Michael D.: ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 10:22pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/7 "2015-07-06T22:22:21Z")
Yes, pmt\_to\_python.py does use numpy. But, it looks like none of the actual build for gnuradio-runtime (including pmt) requires numpy to be installed. So, it’s just used post-install. Hence, maybe why it’s not listed as a direct dependency? - MLD ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 11:05pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/8 "2015-07-06T23:05:00Z")
To clear this up: pmt\_to\_python is a “only” a convenience file, but all Python blocks require numpy. So, if you’re building GNU Radio with Python enabled, CMake should fail without Numpy installed. As you point out, this is a bug in our CMake. M ---
**Author:** ![Volker\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/b5a626/32.png) [@Volker\_S](https://www.ruby-forum.com/u/Volker_S)\ **Post date:** [July 6, 2015, 10:10pm UTC](https://www.ruby-forum.com/t/numpy-question/242603/9 "2015-07-06T22:10:40Z")
Yes, pmt is required for gnuradio-runtime, which in turn is required for anything gnuradio. - MLD