InverseAngleInit: Cutoff not reached for [c:c_1:o_1] in EMC 9.4.4 20260701

EMC
1

I am using EMC Setup v5.3 (July 16, 2026) together with the Windows executable EMC v9.4.4 built Jul 21, 2026.

A PCFF polymer system that was successfully built with an older EMC release now fails immediately during structure construction with:

Error: core/types/inverse/angle.c:462 InverseAngleInit:
Cutoff not reached for [c:c_1:o_1].

The same error occurs for both my previously working P(BMA-co-HEMA)/POPPEA model and a new P(BMA-co-HEMA)/OPEA model, so it does not appear to be specific to the new molecule.

I also tested field_inverse = 0.001 and field_inverse = 0.01; both fail at the same angle type.

The generated build script correctly contains:

types = {inverse -> {cutoff -> 0.01}, cff -> {pair -> {active -> true, mode -> repulsive}}};

The error occurs at 0% construction, before any sites are placed.

Could this be related to the updated inverse-angle probability calculation in recent releases?

I can provide the minimal .esh file if needed.

2

Dear user,

Providing your .esh would of course always help identifying the cause of your issue. As to how EMC works: inverse probabilities are constructed upon first use, which means this error always at the beginning of your simulation. As to your suspicion: no changes have been made to this part of the code since the last release.

In summary: please provide us your .esh and let’s take things from there.

4

Here is the complete .esh file:

ITEM        OPTIONS

project     BMA_HEMA_OPEA
field       pcff
density     0.6
number      true
replace     true
ITEM        END

ITEM        GROUPS

EndCap      *C, 1,OPEA:1, 1,OPEA:2, 1,BMA:1, 1,BMA:2, 1,HEMA:1, 1,HEMA:2

OPEA        C(C(=O)OCCOc1ccccc1)C, 1,OPEA:2, 2,OPEA:1, 1,EndCap:1, 2,EndCap:1

BMA         C(C)(C(=O)OCCCC)C, 1,BMA:2, 2,BMA:1, 1,HEMA:2, 2,HEMA:1, 1,EndCap:1, 2,EndCap:1

HEMA        C(C)(C(=O)OCCO)C, 1,HEMA:2, 2,HEMA:1, 1,BMA:2, 2,BMA:1, 1,EndCap:1, 2,EndCap:1

ITEM        END

ITEM        CLUSTERS

target_chain    block, 11
opea_chain      block, 8

ITEM        END

ITEM        POLYMERS

target_chain
1           BMA,4, HEMA,1, BMA,4, HEMA,1, BMA,4, HEMA,1, BMA,4, HEMA,1, BMA,4, HEMA,1

opea_chain
1           OPEA,25

ITEM        END
5

I am assuming your connectivities for your monomers are as follows:

#!/usr/bin/env emc.pl

# Options section

ITEM	OPTIONS

project		BMA_HEMA_OPEA
field		pcff
density		0.6
number		true
replace		true
emc_execute	true

ITEM	END	# OPTIONS

# Groups section

ITEM	GROUPS

EndCap		*C, &
		1,OPEA:1, 1,OPEA:2, 1,BMA:1, 1,BMA:2, 1,HEMA:1, 1,HEMA:2

OPEA		*C(C(=O)OCCOc1ccccc1)C*, &
		1,OPEA:2, 2,OPEA:1, 1,EndCap:1, 2,EndCap:1

BMA		*C(C)(C(=O)OCCCC)C*, &
		1,BMA:2, 2,BMA:1, 1,HEMA:2, 2,HEMA:1, 1,EndCap:1, 2,EndCap:1

HEMA		*C(C)(C(=O)OCCO)C*, &
		1,HEMA:2, 2,HEMA:1, 1,BMA:2, 2,BMA:1, 1,EndCap:1, 2,EndCap:1

ITEM	END	# GROUPS

# Clusters section

ITEM	CLUSTERS

target_chain	block, 11
opea_chain	block, 8

ITEM	END	# CLUSTERS

# Polymers section

ITEM	POLYMERS

target_chain
1		BMA,4, HEMA,1, BMA,4, HEMA,1, BMA,4, HEMA,1, BMA,4, HEMA,1, BMA,4, HEMA,1

opea_chain
1		OPEA,25

ITEM	END	# POLYMERS

Unfortunately, I am not able to reproduce your observed behavior with this assumption using the current EMC release (i.e. the system builds normally). If my above assumption is correct, might I suggest you try using Windows Subsystem for Linux (WSL) with e.g. Ubuntu as Linux version (thus using the Linux EMC version) and see if you still run into the same problems?