calculates the probability of any given year following a group of events; as an example After {C_Date 1000;}; will yield 1 for all dates after 1000 and 0 for all dates before.
See [Program Operation] [Mathematical Methods]
defines the x-axis limits for the plot produced - remember that the labels on the left of the plot obscure some of the area so make min a bit lower than you actually need.
See [Program Operation]
calculates the probability of any given year preceding a group of events; similar to After.
See [Program Operation] [Mathematical Methods]
used to define which events in a model are from well defined periods and to estimate the boundaries of these periods using a model of uniform distribution; must always be used in conjunction with Sequence as in:
Sequence {Boundary; Phase {R_Date 750 50; R_Date 800 60;}; Boundary;};
it can be used between phases to estimate the boundary between abutting phases.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used to combine calendar dates; a chi squared test is performed.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used to generate a gaussian probability distribution about a calendar age with a given error term (1 sigma); if no error is given a single spike is produced; if two errors are given an asymmetric distribution is generated.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used within a function group to ensure that only the result of the function is plotted in any outer group: thus the main plot for
Phase {R_Date "A" 900 60; Combine "B" {R_Date 950 50; C_Date 1000 50; Calculate;};};
will only display distributions A and B and not the details of the combination.
See [Program Operation]
used to combine probability distributions of all types.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
this command has no effect and is equivalent to starting a line with an exclamation mark thus Ccomment "test comment"; is equivalent to !test comment which is more normally used.
See [Program Operation]
used to produce a correlation plot between two events which are otherwise related by some stratigraphic relationships; for example the commands
Sequence {R_Date "A" 1000 100; R_Date "B" 990 50; Correlate "R" "A" "B";};
will produce a correlation plot R for the two dates A and B.
See [Archaeological Considerations] [Program Operation]
used to change the calibration curve used within the present group; note that the curve will be reset at the end of a phase, sequence etc; this command allows the user to calibrate a mixture of marine and terrestrial samples; the filename should always be specified the first time a calibration curve is used within one calculation.
See [Calibration Data]
used to combine dates when the age separation between them is known; this is most likely to be used for `wiggle matching' of radiocarbon dates made on tree ring sequences; for example three tree rings each separated by 100 years could be combined using
D_Sequence {R_Date 1100 50; Gap 100; R_Date 1020 50; Gap 100; R_Date 930 50;};
This is in fact similar to
Combine {R_Date 1100 50; Gap 200; R_Date 1020 50; Gap 100; R_Date 930 50;};
although the latter would behave differently if nested in a sequence since it will generate a resultant distribution.
IMPORTANT: dates are entered in chronological order (oldest first) although they can be displayed in reverse order (youngest at the top) by selecting the
[Options|System options|reverse order] option.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
Used in association with Curve to generate a local marine calibration curve using the Delta_R offsets as defined in Stuiver and Braziunas 1993; reservoir values are available online from Queen's University Belfast; the basic marine curve is supplied with this program; to generate a marine curve for Iceland, for example, the commands:
Curve "marine98.14c"; Delta_R 49 19;
could be used; this function offsets the calibration curve in radiocarbon years.
See [Calibration Data] [Mathematical Methods]
used for calculating the time difference between two dates; this function will only work within a Phase a Sequence or a V_Sequence; to calculate a difference distribution between two unconstrained dates use the commands
Phase { R_Date "A" 900 50; R_Date "B" 800 50; Difference "R" "B" "A";};
where the resultant distribution R = B-A.
See [Archaeological Considerations] [Program Operation]
defines the site dose rate for luminescence type dating methods within a group; see also Year and Error; dose rates can be given in scientific notation for example Dose 1.3E-6;.
See [Archaeological Considerations] [Program Operation]
used for defining errors proportional to the age within a group; intended for use with Dose; if a series of events is being combined with Combine the error will be applied after combination.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used to determine the distribution of an event which is constrained in some way by the model but which has no direct dating information. A model consisting almost entirely of events can be constructed to check the effective prior distributions for the model.
See [Example]
used to multiply dates within a group by a set factor (as measured from the present which is defined by Year); this command is not expected to be used much except possibly in combination with Dose.
See [Mathematical Methods]
calculates a probability distribution for the first event in a group; it can be used either with its own group as in
First "f" {R_Date 1000 100; R_Date 1100 100};
or to calculate the start of another group as in
Phase {First "f"; R_Date 1000 100; R_Date 1100 100;};
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
this command is intended primarily for use with D_Sequence (no gap error) and V_Sequence (with gap error); it can also be used in Sequence (no gap error) to ensure a gap between events in a sequence and in Combine (no gap error) where it functions rather like Offset.
See [Program Operation]
used to calculate the interval between events in a sequence; for example
Sequence {R_Date "A" 900 50; Interval "R"; R_Date "B" 800 50;};
will find the expected interval between A and B; the same thing can be achieved with the more general command Difference.
See [Archaeological Considerations] [Program Operation] [Explanatory notes]
used to calculate the probability distribution for the last event in a group; similar in operation to First.
See [Archaeological Considerations] [Program Operation]
used to draw a horizontal line in multiple plots.
See [Program Operation]
used to insert a label in a multiple plot.
See [Program Operation]
used to mix radiocarbon calibration curves; name1 and name2 must already have been defined using Curve statements; proportion2 and prop2err are the proportion and error in the proportion of the second curve in the mixture.
See [Calibration Data] [Mathematical Methods]
used to offset distributions (a positive offset makes the distribution younger); for example an event dated by wood which had an age of 30+-10 years would have a probability distribution given by R_Date 3000 60; Offset 30 10;.
Offset should not be used for Delta_R corrections of marine samples as the offset is performed after calibration: in these cases Delta_R should be used.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used in exactly the same way as Phase except that the relative order of the events will be determined by the program.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
produces a page break in a multiple plot.
See [Program Operation]
used to group events between which there are no known relationships but which may all share some relationship.
See [Archaeological Considerations] [Program Operation]
used to group dates together for plotting purposes only.
See [Producing a multiple plot]
used to access stored probability distributions (which could be provided by the user or saved from previous calculations); thus Prior "OxA-3000"; will retrieve the distribution from the file OXA3000.14D; to refer to a file already defined within a previously calculated sequence or phase use the command in the form Prior "@OxA-3000"; which will retrieve the file OXA3000.14S; the filename can be used to specify a file which has not been generated by an earlier part of this calculation.
See [Archaeological Considerations] [File Formats]
used to question the position of an event for example in a sequence; it is exactly equivalent to ending the previous command with a question mark instead of a semicolon; thus C_Date 1000 50; Question; is equivalent to the more normally used C_Date 1000 50? the commands
Sequence {R_Date "A" 900 50; R_Date "B" 800 50? R_Date "C" 700 50;};
will not use B in calculating the sequence but will give the probability that it occupies this position in the sequence.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used to combine radiocarbon dates before calibration; a chi squared test is performed.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used for radiocarbon dates which are to be calibrated.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used for seeing what kind of radiocarbon measurement would be expected for a sample with a given calendar age; thus R_Simulate 1066 50; will give a radiocarbon date that you might expect to get for the battle of Hastings assuming the error you expect from the radiocarbon lab is +-50; each time the command is called a different radiocarbon date will be produced.
See [Archaeological Considerations] [Program Operation]
Used in association with Curve to generate a calibration curve for some sort of reservoir with a known age constant; a fresh water lake might have a mean reservoir age (in calendar years) of 80+/-20 years a suitable smoothed curve might be generated by the commands:
Curve "CAL10.DTA"; Reservoir 80 20;
the reservoir is assumed to be small compared to the atmosphere; mixing within the reservoir is assumed to be good; a simple box diffusion model is used.
See [Calibration Data] [Mathematical Methods]
allows the information that one event precedes another to be incorporated into the resultant probability distributions; the sequence can contain phases and functions as well as simple dated events; TAQ and TPQ functions can also be used to allow for termini ante quem and termini post quem. IMPORTANT: dates are entered in chronological order (oldest first) although they can be displayed in reverse order (youngest at the top) by selecting the
[Options|System options|reverse order] option.
See [Archaeological Considerations] [Program Operation]
used for shifting one probability by another; this function will only work within a Phase a Sequence or a V_Sequence; as an example of its use consider D which lies as long after C as B is after A where we have dates for A, B and C:
Phase
{
R_Date "A" 1200 60;
R_Date "B" 1100 60;
R_Date "C" 1000 60;
Difference "R" "B" "A";
Shift "D" "C" "R";
};
where the resultant distribution R = B-A and so D = C+R = C+B-A
as required.
used to calculate the span of a phase, sequence or other group which is defined as the probability distribution for the difference between the first and last events of a group; thus to find the span of a phase the necessary commands might be:
Phase {R_Date 1000 100; R_Date 900 60; Span "R";};
See [Archaeological Considerations] [Program Operation]
used for adding probability distributions to arrive at the best estimate for the chronological distribution of the events; differs from Combine in that ranges are expanded rather than reduced with additional information; the resultant distribution does not relate to a single event and so cannot be used as the input to other functions; the elements within the sum are treated as a phase and can be constrained in a similar way; note that, for example, the 95% range for a Sum distribution give an estimate for the period in which 95% of the events took place not the period in which one can be 95% sure all of the events took place.
See [Archaeological Considerations] [Program Operation]
similar to TPQ but for a terminus ante quem.
See [Archaeological Considerations] [Program Operation]
(terminus post quem) used within a sequence to force all items later in the sequence to follow the items in the TPQ group; all items earlier in the sequence are not directly affected; thus if a coin with a date of 1066 is found between two samples in a sequence the second sample B in the sequence must be later than 1066 but that is the only direct constraint:
Sequence {R_Date "A" 1050 60; TPQ {C_Date 1066;}; R_Date "B" 1030 60;};
B will be forced after 1066 but A will not have to be before 1066; note that A will be indirectly affected because of the constraint that A is before B.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
similar to D_Sequence except that the gaps can be defined with errors; the calculations involved are actually rather different and might fail to give a result if the error is very low; the calculations may also become slow if the agreement between the results is poor. IMPORTANT: dates are entered in chronological order (oldest first) although they can be displayed in reverse order (youngest at the top) by selecting the
[Options|System options|reverse order] option.
See [Archaeological Considerations] [Program Operation] [Mathematical Methods]
used to refer to an event already defined somewhere else in the stratigraphic sequence.
See [Archaeological Considerations] [Program Operation]
used to define the year of measurement for luminescence dates or anything for which a an age factor or proportional error term is required; if this is not defined the year is assumed to be 1950.
See [Archaeological Considerations] [Program Operation]