MULTIG(1)

👑 MULTIG 👑 (that's section 1 of the manual, bestie)

🌸 NAME 🌸

multig — the manual page for multig 2.9.3. yes that's literally it, that's the whole name section 💅

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✨ SYNOPSIS ✨

multig [-q] [-V] [-u|-T|-G|-A|-B] [-e#|-e#:#]
       [-m#] [-f#] [-D#|-r#|-l#] [infile [outfile]]

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🦋 DESCRIPTION 🦋

okay so picture this: multig reads undirected loop-free graphs and replaces their edges with multiple edges in all possible ways (multiplicity at least 1, no zero-multiplicity shenanigans). and the best part? multigraphs that are isomorphic and came from the same input get suppressed — gone, deleted, not invited to the party. 🙈 and if your input graphs were non-isomorphic to begin with, then the output graphs are also non-isomorphic. it's giving consistency, it's giving structural integrity, we love to see it. 🫶

• -e# | -e#:# — you're specifying a value, or a range, for the total number of edges counting multiplicities. yes, multiplicities count. every single one. ✨
• -m# — maximum edge multiplicity. and heads up: the minimum is 1. always. (minimum is 1) 🌸
• -D# — upper bound on the maximum degree. a lil ceiling for your degrees, as a treat. 🎀
• -r# — make it regular of the specified degree. ⚠️ incompatible with -l, -D, -e — these options do NOT get along, do not put them in the same group chat. 💀
• -l# — make regular multigraphs with multiloops, degree #. ⚠️ incompatible with -r, -D, -e. same energy, different vibe. multiloops are the main character here. 🌀
• -f# — use the group that fixes the first # vertices setwise. setwise, bestie. not pointwise. respect the distinction. 👑
• -V — read the T format as produced by vcolg and obey the vertex colours when computing the automorphism group. and if -T or -G is used as the output format, a list of the input colours is included too. 🎨

📢 the requirement, fr fr: either -l, -r, -D, -e or -m with a finite maximum must be given. there is no vibing your way out of this one.

• -T — use a simple text output format, which looks like nv ne {v1 v2 mult}. simple. clean. iconic. ✨
• -G — like -T but it includes the group size as the third item (only if it's less than 10^10, so like, don't get too ambitious). 🔥

🫶 important footnote: the group size does not include exchange of isolated vertices. isolated vertices are just out here living their lives, not counted. 🦋

• -A — write as the upper triangle of an adjacency matrix, row by row, including the diagonal, and preceded by the number of vertices. triangle. upper. diagonal included. no notes. 📐
• -B — write as an integer matrix preceded by the number of rows and number of columns, where -f determines the number of rows. yes, -f is running the row count now, she's got a second job. 💅
• -u — no output, just count them. that's it. that's the whole option. counting only, no receipts. 🔢
• -q — suppress auxiliary information. shhh. quiet. 🤫

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💖 the sign-off 💖

this page is for multig 2.9.3, and it's dated September 2026 — so yeah, she's current, she's fresh, she ate and left no crumbs. go build some multigraphs, bestie. 🎀🦋✨💜