FeynCalc2FORM[exp] displays exp in FORM syntax.
FeynCalc2FORM[file, x] writes x in FORM syntax to a file.
FeynCalc2FORM[file, x == y] writes x=y to a file in FORM syntax.
The capabilities of this function are very limited, so you should not expect it to easily handle large and complicated expressions.
FORM2FeynCalc\text{FORM2FeynCalc}
MT[\[Mu], \[Nu]] FV[p, \[Rho]] y^2/d
FeynCalc2FORM[%];\frac{y^2 \overline{p}^{\rho } \bar{g}^{\mu \nu }}{d}
(y^2d_(mu,nu)p(ro))/d
LC[\[Alpha], \[Beta], \[Delta], \[Rho]]
FeynCalc2FORM[%];\bar{\epsilon }^{\alpha \beta \delta \rho }
(-i_)*e_(al,be,de,ro)
DiracTrace[GA[\[Mu], \[Nu], \[Rho], \[Sigma]]]
FeynCalc2FORM[%];\text{tr}\left(\bar{\gamma }^{\mu }.\bar{\gamma }^{\nu }.\bar{\gamma }^{\rho }.\bar{\gamma }^{\sigma }\right)
g_(0,mu)g_(0,nu)g_(0,ro)*g_(0,si)
DiracTrace[GA[\[Mu], \[Nu]]] DiracTrace[GA[\[Mu], \[Rho]]]
FeynCalc2FORM[%];\text{tr}\left(\bar{\gamma }^{\mu }.\bar{\gamma }^{\nu }\right) \;\text{tr}\left(\bar{\gamma }^{\mu }.\bar{\gamma }^{\rho }\right)
g_(0,mu)g_(0,nu)g_(1,mu)*g_(1,ro)
t = DiracSimplify[DiracTrace[GA[\[Mu], \[Nu], \[Rho], \[Sigma]] . GS[p, q]]]4 \overline{p}^{\nu } \overline{q}^{\mu } \bar{g}^{\rho \sigma }-4 \overline{p}^{\mu } \overline{q}^{\nu } \bar{g}^{\rho \sigma }-4 \overline{p}^{\rho } \overline{q}^{\mu } \bar{g}^{\nu \sigma }+4 \overline{p}^{\rho } \overline{q}^{\nu } \bar{g}^{\mu \sigma }+4 \overline{p}^{\mu } \overline{q}^{\rho } \bar{g}^{\nu \sigma }-4 \overline{p}^{\nu } \overline{q}^{\rho } \bar{g}^{\mu \sigma }+4 \overline{p}^{\sigma } \overline{q}^{\mu } \bar{g}^{\nu \rho }-4 \overline{p}^{\sigma } \overline{q}^{\nu } \bar{g}^{\mu \rho }+4 \overline{p}^{\sigma } \overline{q}^{\rho } \bar{g}^{\mu \nu }-4 \overline{p}^{\mu } \overline{q}^{\sigma } \bar{g}^{\nu \rho }+4 \overline{p}^{\nu } \overline{q}^{\sigma } \bar{g}^{\mu \rho }-4 \overline{p}^{\rho } \overline{q}^{\sigma } \bar{g}^{\mu \nu }+4 \bar{g}^{\mu \nu } \bar{g}^{\rho \sigma } \left(\overline{p}\cdot \overline{q}\right)+4 \bar{g}^{\mu \sigma } \bar{g}^{\nu \rho } \left(\overline{p}\cdot \overline{q}\right)-4 \bar{g}^{\mu \rho } \bar{g}^{\nu \sigma } \left(\overline{p}\cdot \overline{q}\right)
FeynCalc2FORM["fc2ftest.f", L == t];TableForm[ReadList[If[$OperatingSystem === "MacOS", ":", ""] <> "fc2ftest.f", String]]\begin{array}{l} \;\text{Indices $\backslash \backslash $[Mu],$\backslash \backslash $[Nu],$\backslash \backslash $[Rho],$\backslash \backslash $[Sigma];} \\ \;\text{Vectors OPEDelta,p,q;} \\ \;\text{write statistics;} \\ \;\text{Local L = ( } \\ \;\text{4*d$\_$(mu,si)*d$\_$(nu,ro)*q.p-4*d$\_$(mu,ro)*d$\_$(nu,si)*q.p+4*d$\_$(mu,nu)*d$\_$(ro,si)*q.p+} \\ \;\text{4*d$\_$(ro,si)*p(nu)*q(mu)-4*d$\_$(nu,si)*p(ro)*q(mu)+4*d$\_$(nu,ro)*p(si)*q(mu)-} \\ \;\text{4*d$\_$(ro,si)*p(mu)*q(nu)+4*d$\_$(mu,si)*p(ro)*q(nu)-4*d$\_$(mu,ro)*p(si)*q(nu)+} \\ \;\text{4*d$\_$(nu,si)*p(mu)*q(ro)-4*d$\_$(mu,si)*p(nu)*q(ro)+4*d$\_$(mu,nu)*p(si)*q(ro)-} \\ \;\text{4*d$\_$(nu,ro)*p(mu)*q(si)+4*d$\_$(mu,ro)*p(nu)*q(si)-4*d$\_$(mu,nu)*p(ro)*q(si) ); } \\ \;\text{ } \\ \;\text{print;} \\ \;\text{.end} \\ \end{array}
If[FileNames["fc2ftest.f"] =!= {}, DeleteFile["fc2ftest.f"]];Clear[t];