diff --git a/README.md b/README.md index 258f7a6..45ea118 100644 --- a/README.md +++ b/README.md @@ -1,3 +1,75 @@ clojure matrix-repl thing, the last two methods in src/matrix/core.clj are the only interesting bits src/matrix/core.clj is the only file with interesting stuff + +\*actual\* usage example: +``` +matrix.core=> (matrix-repl [[1 1 -1 -5] [5 -1 1 -1] [-1 3 -2 1]] :yeah) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 5 -1 1 │ -1 ┃ +┃ -1 3 -2 │ 1 ┃ +┗ ┛ +(add-mul 5 2 1) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 14 -9 │ 4 ┃ +┃ -1 3 -2 │ 1 ┃ +┗ ┛ +(add 0 2) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 14 -9 │ 4 ┃ +┃ 0 4 -3 │ -4 ┃ +┗ ┛ +(add-mul -4/14 1 2) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 14 -9 │ 4 ┃ +┃ 0 0 -3/7 │ -36/7 ┃ +┗ ┛ +(mul 7 2) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 14 -9 │ 4 ┃ +┃ 0 0 -3 │ -36 ┃ +┗ ┛ +(mul -1/3 2) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 14 -9 │ 4 ┃ +┃ 0 0 1 │ 12 ┃ +┗ ┛ +(add-mul 9 2 1) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 14 0 │ 112 ┃ +┃ 0 0 1 │ 12 ┃ +┗ ┛ +(mul 1/14 1) +┏ ┓ +┃ 1 1 -1 │ -5 ┃ +┃ 0 1 0 │ 8 ┃ +┃ 0 0 1 │ 12 ┃ +┗ ┛ +(add 2 0) +┏ ┓ +┃ 1 1 0 │ 7 ┃ +┃ 0 1 0 │ 8 ┃ +┃ 0 0 1 │ 12 ┃ +┗ ┛ +(add-mul -1 1 0) +┏ ┓ +┃ 1 0 0 │ -1 ┃ +┃ 0 1 0 │ 8 ┃ +┃ 0 0 1 │ 12 ┃ +┗ ┛ +print-equations +x = -1 +y = 8 +z = 12 +┏ ┓ +┃ 1 0 0 │ -1 ┃ +┃ 0 1 0 │ 8 ┃ +┃ 0 0 1 │ 12 ┃ +┗ ┛ diff --git a/src/matrix/core.clj b/src/matrix/core.clj index 6fe6354..f5e60c9 100644 --- a/src/matrix/core.clj +++ b/src/matrix/core.clj @@ -135,10 +135,68 @@ m)) ;; repl commands +(defn fmt-num + "Format a number, empty string for 1" + [n] + (if (= 1 n) + "" + (str n))) + +(defn mid-sign + "Format a term as either '+ n' or '- n'" + [n] + (if (pos? n) + (str "+ " (fmt-num n)) + (str "- " (fmt-num (* -1 n))))) + +(defn single-term + [val name first] + (if (zero? val) + "" + (str (if first + (fmt-num val) + (mid-sign val)) + name))) + +; could be generalized +(defn equation-from-row + "Write a pretty equation from one row of an augmented matrix" + ([row] (apply equation-from-row row)) + ([x eq] (str (single-term x "x" true) + " = " + eq)) + ([x y eq] + (let [x (single-term x "x" true) + y (single-term y "y" (empty? x))] + (str x + (if (not-empty x) " ") + y + (if (not-empty y) " ") + "= " eq))) + ([x y z eq] + (let [x (single-term x "x" true) + y (single-term y "y" (empty? x)) + z (single-term z "z" (and (empty? x) (empty? y)))] + (str x + (if (not-empty x) " ") + y + (if (not-empty y) " ") + z + (if (not-empty z) " ") + "= " eq)))) + +(defn print-matrix-equations + [m] + (do + (last (for [row m] + (println (equation-from-row row)))) + m)) + (defn swap [n m] #(swap-rows % n m)) (defn add [from to] #(add-rows % from to)) (defn add-mul [n from to] #(add-rows-with-mul % n from to)) -(defn mul [n at] #(mul-row % n at)) +(defn mul [n at] #(mul-row % n at)) +(def print-equations print-matrix-equations) (defn apply-input [m] @@ -157,7 +215,6 @@ (pprint-matrix m add-bar) (iterate (comp #(pprint-matrix % add-bar) apply-input) m))) - (defn -main "I don't do a whole lot ... yet." [& args] @@ -167,3 +224,11 @@ got) matrix-repl last))) + +; TODO: actual parsing of row operations +; TODO: parse equations (easy, but requires context (e.g. x = 1 could be any number of variables)) +; TODO: undoing + ; will have to have a higher level thing for storing state +; TODO: solving id-matrix +; TODO: solving gaussian-eliminated matrix +; TODO: automation