### DES : Execution fails on C_l's negative and message TTanhReionization_zreFromOptDepth: Did not converge to optical depth

Posted:

**March 01 2022**Hi !

I tried to make run chains with DES survey but cosmomc failed up to 3 hours of computing.

Here the des_curvature.ini that I am using :

1) You can see that I have put a prior on Omega_k, I don't know if it is useful : if someone could confirm the utility of adding this prior.

2) Secondly, below the log file of the run which fails :

2.1) I don't understand why I get the message :

Have got to put a prior on tau ? I tried also to make run by putting :

or even only with :

but it gives very strange cosmology contours. Which is the correct syntax to avoid this message

2.2) You can notice that program stops since :

From what I understood, he stops because it has evaluted negative C_l, isn't it ?

Any help is welcome to solve the points 1), 2.1) and 2.2)

Best regards

I tried to make run chains with DES survey but cosmomc failed up to 3 hours of computing.

Here the des_curvature.ini that I am using :

Code: Select all

```
#general settings, test file without require Planck likelihood code to be installed.
#see test_planck.ini for test file including Planck clik likelihoods
#DES 1-yr joint
DEFAULT(batch3/DES_lensing.ini)
#general settings
DEFAULT(batch3/common.ini)
param[omegak] = 0. -0.5 0.5 0.01 0.01
#high for new runs, to start learning new proposal matrix quickly
MPI_Max_R_ProposeUpdate = 30
propose_matrix= planck_covmats/base_TT_lensing_lowE_lowl_plikHM.covmat
#Folder where files (chains, checkpoints, etc.) are stored
root_dir = chains/
#Root name for files produced
file_root=des_omegak
#action= 0 runs chains, 1 importance samples, 2 minimizes
#use action=4 just to quickly test likelihoods
action = 0
#Don't need to set this if OMP_NUM_THREADS set appropriately
num_threads = 0
#if you want to get theory cl for test point
#test_output_root = output_cl_root
start_at_bestfit =F
feedback=1
use_fast_slow = T
#turn on checkpoint for real runs where you want to be able to continue them
checkpoint = T
#sampling_method=7 is a new fast-slow scheme good for Planck
sampling_method = 7
dragging_steps = 3
propose_scale = 2
#Set >0 to make data files for importance sampling
indep_sample=10
#these are just small speedups for testing
get_sigma8=T
```

2) Secondly, below the log file of the run which fails :

Code: Select all

```
Chain:0 drag accpt: 0.4849885 fast/slow 58.51421 slow: 2392
Chain:1 drag accpt: 0.5351521 fast/slow 58.67863 slow: 1867
Chain:3 drag accpt: 0.3510825 fast/slow 58.79749 slow: 2953
Chain:2 drag accpt: 0.4091374 fast/slow 58.76303 slow: 2819
Chain:0 drag accpt: 0.4835083 fast/slow 58.42980 slow: 2443
Chain:3 drag accpt: 0.3547736 fast/slow 58.73333 slow: 3000
Chain:0 drag accpt: 0.4845815 fast/slow 58.36338 slow: 2496
Chain:1 drag accpt: 0.5370844 fast/slow 58.58159 slow: 1912
Chain 3 MPI communicating
Chain 2 MPI communicating
Chain 4 MPI communicating
Chain 1 MPI communicating
Current convergence R-1 = 8.874245 chain steps = 2777
slow changes 2534 power changes 0
updating proposal density
Chain:3 drag accpt: 0.3547297 fast/slow 58.65588 slow: 3060
Chain:0 drag accpt: 0.4836976 fast/slow 58.29717 slow: 2544
Chain:2 drag accpt: 0.4063429 fast/slow 58.61038 slow: 2890
Chain:1 drag accpt: 0.5373135 fast/slow 58.40754 slow: 1963
Chain:0 drag accpt: 0.4808362 fast/slow 58.16468 slow: 2605
TTanhReionization_zreFromOptDepth: Did not converge to optical depth
tau = 0.211094049991010 optical_depth = 0.305066709379731
50.0000000000000 49.9938964843750
(If running a chain, have you put a constraint on tau?)
Chain:3 drag accpt: 0.3572417 fast/slow 58.57617 slow: 3105
Chain:1 drag accpt: 0.5339105 fast/slow 58.21110 slow: 2018
Chain:0 drag accpt: 0.4655002 fast/slow 58.03076 slow: 2698
Chain:3 drag accpt: 0.3607543 fast/slow 58.46537 slow: 3148
Chain:2 drag accpt: 0.4002541 fast/slow 58.47289 slow: 2969
Chain:1 drag accpt: 0.5347092 fast/slow 58.10993 slow: 2065
Chain:0 drag accpt: 0.4664723 fast/slow 57.93632 slow: 2748
Calculator_CAMB: negative C_l (could edit to silent error here)
MpiStop: 1
Abort(-1644241136) on node 1 (rank 1 in comm 0): application called MPI_Abort(MPI_COMM_WORLD, -1644241136) - process 1
```

Code: Select all

```
TTanhReionization_zreFromOptDepth: Did not converge to optical depth
tau = 0.211094049991010 optical_depth = 0.305066709379731
```

Code: Select all

```
param[omegak] = 0. -0.2 0.2 0.01 0.01
param[tau] = 0.05430842
```

Code: Select all

`param[tau_reio] = 0.05430842 0.04 0.06 0.001 0.001 `

?TTanhReionization_zreFromOptDepth: Did not converge to optical depth

2.2) You can notice that program stops since :

Code: Select all

```
Calculator_CAMB: negative C_l (could edit to silent error here)
MpiStop: 1
```

Any help is welcome to solve the points 1), 2.1) and 2.2)

Best regards