# Is a bug about stream\_mux block?

**URL:** <https://www.ruby-forum.com/t/is-a-bug-about-stream-mux-block/240045>\
**Category:** GNU Radio\
**Created:** [March 25, 2014, 4:19pm UTC](https://www.ruby-forum.com/t/is-a-bug-about-stream-mux-block/240045 "2014-03-25T16:19:13Z")\
**Posts on this page:** 1\
**Page:** 1

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**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:** [March 25, 2014, 4:19pm UTC](https://www.ruby-forum.com/t/is-a-bug-about-stream-mux-block/240045/1 "2014-03-25T16:19:13Z")

</div>

Hi Experts,  
As follow is my program to test stream\_mux block. I found when  
dat1\_num+dat2\_num \> 8192, the result is wrong.  
Is there something I have made a mistake?  
My gnuradio version is v3.7.4git-35-g1092e685

#!/usr/bin/env python  
from gnuradio import gr  
from gnuradio import blocks  
if **name** == ‘ **main** ’:  
tb = gr.top\_block ()  
dat1\_num = 3  
dat2\_num = 8191

```
    dat1 = [1] * dat1_num
    dat1_src = blocks.vector_source_f(dat1)

    dat2 = [2] * dat2_num
    dat2_src = blocks.vector_source_f(dat2)

    tmp_dat = dat1 + dat2
    tmp_dst = blocks.vector_sink_f()

    mux = blocks.stream_mux(gr.sizeof_float, (dat1_num, dat2_num))

    tb.connect((dat1_src, 0), (mux, 0))
    tb.connect((dat2_src, 0), (mux, 1))
    tb.connect(mux, tmp_dst)
    tb.run ()
    if (tuple(tmp_dat) == tmp_dst.data()):
        print "fine"
    else:
        print len(tmp_dst.data())

```

–  
Thanks  
Tiankun