# nupack3.2.2 (multi tube design problem)

**URL:** https://forum.eternagame.org/t/nupack3-2-2-multi-tube-design-problem/2938
**Category:** Tools
**Created:** [July 3, 2018, 7:33pm UTC](https://forum.eternagame.org/t/nupack3-2-2-multi-tube-design-problem/2938 "2018-07-03T19:33:00Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![ravanhadi](https://forum.eternagame.org/letter_avatar_proxy/v4/letter/r/59ef9b/32.png) [@ravanhadi](https://forum.eternagame.org/u/ravanhadi)
#### Post date: [July 3, 2018, 7:33pm UTC](https://forum.eternagame.org/t/nupack3-2-2-multi-tube-design-problem/2938/1 "2018-07-03T19:33:00Z")

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The nupack package in its latest version (3.2.2) has added  
multi-tube design capabilities. This feature allows the user to design a reaction path. To write a multi-tube script, the user needs to determine the on-target and off-target complexes. In the nupack script, the on-target complex codes can be easily written while the off-target code cannot be easily written. I studied software manual several times, but I could not find out the principle behind the writing off-target code. Can anyone help me write the off-target code?

An example: **off-target code are shown in bold letters.**

tube Step\_\_0 = C X B A  
Step\_\_0.C.conc[M] = 1e-08  
Step\_\_0.X.conc[M] = 1e-08  
Step\_\_0.B.conc[M] = 1e-08  
Step\_\_0.A.conc[M] = 1e-08  
**Step\_\_0.offtargets = {maxsize = 2} - {X\_\_A, I\_s B\_s}**

tube Step\_\_1 = X\_\_A  
Step\_\_1.X\_\_A.conc[M] = 1e-08  
**Step\_\_1.offtargets = {maxsize = 2} + {X, A}**

tube Step\_\_2 = X\_\_A\_\_B  
Step\_\_2.X\_\_A\_\_B.conc[M] = 1e-08  
**Step\_\_2.offtargets = {maxsize = 2} + {B, X\_\_A}**

tube Step\_\_3a = X\_\_A\_\_B\_\_C  
Step\_\_3a.X\_\_A\_\_B\_\_C.conc[M] = 1e-08  
**Step\_\_3a.offtargets = {maxsize = 2} + {C, X\_\_A\_\_B}**

tube Step\_\_3b = X A\_\_B\_\_C  
Step\_\_3b.X.conc[M] = 1e-08  
Step\_\_3b.A\_\_B\_\_C.conc[M] = 1e-08  
**Step\_\_3b.offtargets = {maxsize = 2} + {X\_\_A\_\_B\_\_C}**