the sample size was shrinking to zero

[Da Pan]

Dear Laurent,
 
I am trying to simulate a model (attached) using the .par file below:
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//Number of population samples (demes)
2 samples to simulate
//Population effective sizes (number of genes)
37927
45061
//Samples sizes and samples age
24
24
//Growth rates : negative growth implies population expansion
0
0
//Number of migration matrices : 0 implies no migration between demes
3
//migration matrix 0
0.000 0.000
0.000 0.000
//migration matrix 1
0.000 0.0365563
0.0365563 0.000
//migration matrix 2
0.000 0.227558
0.227558 0.000
//historical event: time, source, sink, migrants, new size, growth rate, migr. matrix
7 historical events
5000 0 0 0 1 0.000582994 1
5000 1 1 0 1 0.000582994 1
9500 0 0 0 1 0 2
9500 1 1 0 1 0 2
13250 0 0 0 1 -0.000582994 1
13250 1 1 0 1 -0.000582994 1
16500 0 1 1 1 0 0
//Number of independent loci [chromosome]
5531
//Per chromosome: Number of linkage blocks
1
//per Block: data type, num loci, rec. rate and mut rate + optional parameters
SNP 1 0
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It returns the message "TDemeCollection::adjustDemeSizesCT: Sample size set to 1 in deme 0 at time 1346529 as it was shrinking to zero! Check your par file...!!!".
 
I am confused about this. 
In my model,  demes are only shrinking (backward in time) between 13250 to 16500 at very low growth rate. Then deme 0 migrates to deme 1 and the growth rate is set to 0 at time 16500. Why the size of deme 0 is shrinking to 0 at time 1346529?
 
Thanks a lot for your kind help.
Best,
Da

[Laurent Excoffier]

Hi,

 

I am confused about this.  
In my model,  demes are only shrinking (backward in time) between 13250 to 16500 at very low growth rate. Then deme 0 migrates to deme 1 and the growth rate is set to 0 at time 16500. Why the size of deme 0 is shrinking to 0 at time 1346529? 

Yes, but you did not reset the growth rate to zero in deme zero, hence the message you get. Actually, fsc checks that the population size of all demes does not shrink to zero....

You should add another event to handle this problem

 

laurent

[Da Pan]

Hi,
Thank you for you reply.
Should I add two events to reset the growth rates as follows:

5000 0 0 0 1 0.000582994 1
5000 1 1 0 1 0.000582994 1
9500 0 0 0 1 0 2
9500 1 1 0 1 0 2
13250 0 0 0 1 -0.000582994 1
13250 1 1 0 1 -0.000582994 1

16500 0 0 0 1 0 0
16500 1 1 0 1 0 0

16500 0 1 1 1 0 0

Best wishes,
Da

[Laurent Excoffier]

yes it's the way to go

L