Add normalise[!] to normalise traces by maximum value

src/SAC.jl

@@ -10,6 +10,10 @@ module SAC
 using Compat
 using Compat.LinearAlgebra
 
+@static if VERSION >= v"0.7-"
+    import StatsBase: linreg
+end
+
 import DSP, Dierckx
 import Glob
 import Base: ==, copy, getindex, fft, setindex!, time, write
@@ -37,6 +41,8 @@ export
     modify,
     multiply!,
     multiply,
+    normalise!,
+    normalise,
     read_wild,
     rmean!,
     rotate_through!,
@@ -114,6 +120,14 @@ for (name, abbrev) in copying_funcs
 end
 
 # Build methods which can be used with chaining (`|>`)
+"""Dict with keys given by name of each function to have a chaining version.
+   Where an abbreviated version exists, that is given as the value; otherwise
+   the value is nothing."""
+const chaining_funcs = Dict(
+    copying_funcs...,
+    :normalise! => nothing
+    )
+
 for (name, abbrev) in copying_funcs
     new_name = Symbol(string(name)[1:end-1])
     @eval begin

src/operations.jl

@@ -135,6 +135,24 @@ julia> modify(s, x->x^2)[:depmax]
 """
 modify(s::SACtr, f) = modify!(deepcopy(s), f)
 
+"""
+    normalise!(s::SACtr) -> s
+
+Normalise a SACtr `s` so that its maximum absolute amplitude is unity.
+"""
+function normalise!(s::SACtr)
+    maxval = maximum(abs, s.t)
+    s.t .= s.t./maxval
+    update_headers!(s)
+end
+
+"""
+    normalise(s::SACtr) -> s_new
+
+Return a copy of `s` where the maximum absolute amplitude is unity.
+"""
+normalise(s::SACtr) = normalise!(deepcopy(s))
+
 # Linear operations on multiple traces
 check_traces_combine(s1, s2) = begin s1.b ≈ s2.b && s1.npts == s2.npts ||
     throw(ArgumentError("Traces must have same strart time and length")) end

src/precompile.jl

@@ -54,6 +54,7 @@ function _precompile()
         precompile(divide!, (Array{SACtr}, f1))
         precompile(multiply!, (SACtr, f1))
         precompile(multiply!, (Array{SACtr}, f1))
+        precompile(normalise!, (SACtr,))
         for f2 in number_types
             precompile(cut!, (SACtr, f1, f2))
             precompile(cut!, (Array{SACtr}, f1, f2))

test/operations.jl

@@ -148,4 +148,10 @@ end
         rtrend!(s)
         @test all(s .== s)
     end
+
+    ## Normalisation
+    let s = SACtr(rand(SAC.SACFloat, 100), 0.1), s′ = deepcopy(s)
+        @test all(normalise(s).t .== s′.t./maximum(abs, s.t))
+        @test normalise!(s) == normalise(s′)
+    end
 end