ScalarMul in prime field is a heavy operation.

[supragya]

I analyzed the number of constraints each component presented. One that stuck out was ScalarMul. Is it always going to be heavy operation? or are there optimizations to make it simpler and less taxing on the full circuit at the end? If so, are these under active dev?

binadd1.circom:         non-linear constraints: 16
binadd2.circom:         non-linear constraints: 512
binaddirr.circom:       non-linear constraints: 112
binmul1.circom:         non-linear constraints: 15680
binmulfast1.circom:     non-linear constraints: 885
binmulfast51.circom:    non-linear constraints: 32
binmulfast51_1.circom:  non-linear constraints: 32
binmulfast51_2.circom:  non-linear constraints: 14
binmullessthan51.circom: non-linear constraints: 1
binsub1.circom:         non-linear constraints: 804
chunkedadd.circom:      non-linear constraints: 10
chunkedadd1.circom:     non-linear constraints: 10
chunkedmodulus.circom:  non-linear constraints: 651
chunkify1.circom:       non-linear constraints: 0
inversemodulo1.circom: error[T2046]: Typing error found
modinv.circom:          non-linear constraints: 193
modulus0.circom:        non-linear constraints: 1279
modulus1.circom:        non-linear constraints: 0
modulus2.circom:        non-linear constraints: 3170
modulusagainst2p.circom: non-linear constraints: 25
modulusq1.circom:       non-linear constraints: 0
modulusq2.circom:       non-linear constraints: 3641
point-addition51.circom: non-linear constraints: 3419
pointcompress.circom:   non-linear constraints: 866
scalarmul.circom:       non-linear constraints: 1745401
verify.circom:          non-linear constraints: 3600667

[rahulghangas]

Hi @supragya. thanks for reaching out. Yes, scalarmul is an expensive operation because we had to implement custom big integer arithmetic circuits. There is still room for improvement, but that will happen at some later date since we have other priorities right now. If you're keen to take this up on your end, we will be more than happy to give support in any capacity we can.

Ps - we have already reduced verification constraints by ~30% in #59, which will be merged soon